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Master Thesis

Vegetation survey and GIS-based zonation of the Fond d'AlbaretzForest, Praslin, Seychelles

Author(s): Farrèr, Claudia; Hertach, Martin

Publication Date: 2009

Permanent Link: https://doi.org/10.3929/ethz-a-005791819

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Vegetation Survey and GIS-based Zonation of the FondD’Albaretz Forest, Praslin,Seychelles

Master Thesis in Environmental Sciences

Claudia Farrèr Martin Hertach

March, 2009

Supervision: Dr. Karl Fleischmannand Prof. Peter J. Edwards

Institute of Integrative Biology Zurich

Abstract

The Seychelles flora displays a high degree of endemism and various endemic woody species are

threatened according to the IUCN Red List. The habitats of rare endemic species are often confined to

boulder fields and glacis. Threats are competition by invasive species, forest fires and anthropogenic

habitat degradation. To preserve habitats it is crucial to understand possible interconnections between

the vegetation composition, boulder fields and fire disturbances. We investigated these interconnections

in the area of the Fond D’Albaretz on Praslin Island, which is part of a unique ecological framework and

shelters large interlinked boulder fields.

An extensive database on the vegetation composition was acquired by means of count-plot analysis and

trail transecting. Vegetation zonations were conducted in terms of (i) nativeness, (ii) protection values

and (iii) presence of red listed species. Connection between the occurrence of boulder fields and palms

was studied with a boulder field classification. Spatial data on the occurrence of boulder fields and large

patches of the fern Dicranopteris linearis were gained using satellite images, a geographic information

system (GIS) and the global positioning system (GPS). We also studied post-fire succession by

qualitatively monitoring recently affected areas. To visualize the risk of the induction and the spread of

fire, we produced a fire risk map by including topographic, anthropogenic and vegetation-based

parameters.

Based on prominence values, we found that 75.4% of the vegetation of the Fond D’Albaretz is native

and 20.7% is endemic. Twenty-one different endemic species were found, one of which was classified as

“critically endangered”, one as “endangered”, eleven as “vulnerable”, five as “near threatened” and three

as “least concern”. The vegetation zonation reveals a uniform high protection value of the forest and is

therefore comparable to the Vallée de Mai. We found a significant correlation between the presence of

big boulders and palms (adults and saplings). We also found a moderate significance for the correlation

between the presence of big boulders and threatened species. Interpretation of satellite images and

spatial mapping in the field showed that boulder fields cover an area of 46’437 m2. Resprouting in post-

fire-areas is dominated by endemic species. Most of the area of the Fond D’Albaretz shows a high risk of

spreading or inducing forest fires.

The Fond D’Albaretz is of high ecological importance due to its consistently high protection value, its

comparability to the Vallée de Mai and its relics of original low-altitude forest. The extensive boulder

fields are a hideaway for threatened plant species and protect them from forest fires. The limited

presence of Dicranopteris l. and invasive species suggests that forest fires only rarely affected the Fond

D’Albaretz in the past. The protective force of boulder fields against fires, the absence of preceding

disturbances and the ecological framework seem to be the main reasons for the high ecological value

distinctive of the Fond D’Albaretz. The use of GIS proved to be very valuable and the newly established

fire risk map can be used as a measure to effectively fight forest fires in the future.

Keywords: Ecological importance, Boulder field classification, Protection value, Vegetation zoning,

Dicranopteris l., Red listed woody plant species, Geographic information system, Fire risk map, Fond

D’Albaretz, Praslin, Seychelles.

Acknowledgements

We would like to thank our supervisors Dr. Karl Fleischmann and Prof. Peter J. Edwards from the

Institute of Integrative Biology, ETH, for the possibility to write this master-thesis and for their overall

support.

Special thanks go to Matthieu and Bart LaBuschagne and their families who made this work possible.

Your support with all our daily life and work problems was fantastic. Matt, we thank you for all the

adventurous trips in the forest. We have spent an unforgettable time in the Seychelles!

Many thanks go also to the staff of the Hotel Coco de Mer for cheering up our days, for cooking and

joining us in the staff canteen and for their kindness to provide internet access.

A special thank goes to our neighbours Sudarsana Weliwitigoda and Don Jagath Katugampola with his

wife Ayomi and their daughter Suchali. Thank you for all the good times we spent at your home, the

delicious food and all the nice talks. We will miss you!

Many thanks go to the Plant Conservation Action group (PCA) and especially to Katy Beaver, Frauke

Fleischer-Dogley and Lindsay Chong Seng for administrative help, accommodation and inputs for our

work. It is always a great pleasure to meet you!

We would like to thank Victorin Laboudallon for the insightful walk and helping us with identifying

species.

We are thankful to Justin Prosper from the GIS-Unit at the Policy Planning and Services Division of the

Ministry of Environment on Mahé for providing us with all the needed spatial data of Praslin.

We are grateful to the Praslin Development Fund (PDF), where we thank the chairman Mr. Michel

Gardette for organising us the permit to visit the Fond Ferdinand Nature Reserve and Micheal Gill who

was a great guide in the field and helped us to locate former plots.

Special thanks go to Patrizia Frei for statistical support, inputs for writing the report and unforgettable

two weeks in the Seychelles.

We thank Karsten Rohweder and Hans-Heini Vogel from the Institute of Integrative Biology, ETH, for

providing us with even in the tropics astonishing good working laptops and for their technical support

by finishing our thesis.

Last but not least, we would like to thank our parents for their overall support.

Content

1. Introduction.................................................................................................................................1

2. Methods ........................................................................................................................................4

2.1 General principles .................................................................................................................................... 4

2.2 Trail transecting........................................................................................................................................ 4

2.3 Count-plot analysis................................................................................................................................... 6

2.4 Photo monitoring..................................................................................................................................... 7

2.5 Boulder field classification....................................................................................................................... 8

2.6 Vegetation zoning..................................................................................................................................... 9

2.7 Dicranopteris linearis survey...................................................................................................................... 13

2.8 Boulder field mapping ........................................................................................................................... 14

2.9 Qualitative monitoring of post-fire areas............................................................................................... 14

2.10 Fire risk map......................................................................................................................................... 15

3. Results ....................................................................................................................................... 17

3.1 Fond D’Albaretz - State of the forest ..................................................................................................... 17

3.1.1 General findings ....................................................................................................................... 17

3.1.2 Prominence along trail transects.............................................................................................. 17

3.1.3 Prominence within sampling plots .......................................................................................... 19

3.1.4 Red listed species...................................................................................................................... 21

3.2 Boulder field classification..................................................................................................................... 22

3.2.1 Palms vs. dicotyledonous trees ................................................................................................. 23

3.2.2 Threatened species vs. invasive species .................................................................................... 24

3.3. Vegetation zoning.................................................................................................................................. 25

3.4 Correlation between Dicranopteris l. and invasive species ..................................................................... 26

3.5 Occurrence of boulder fields ................................................................................................................. 27

3.6 Qualitative monitoring of post-fire areas............................................................................................... 27

3.7 Fire risk map........................................................................................................................................... 30

3.8 Trail towards Glacis Noir - State of the forest....................................................................................... 31

3.8.1 Prominence along trail transects.............................................................................................. 31

3.8.2 Vegetation zoning..................................................................................................................... 31

4. Discussion and conclusions ..................................................................................................... 32

4.1 Species composition............................................................................................................................... 32

4.2 Ecological value ...................................................................................................................................... 33

4.3 The role of boulder fields....................................................................................................................... 34

4.4 Future trends .......................................................................................................................................... 34

4.5 Dicranopteris l. and the abundance of invasive species .......................................................................... 35

4.6 Comparison of the Fond D’Albaretz with the adjacent area towards Glacis Noir.............................. 35

4.7 Post fire regeneration ............................................................................................................................. 36

4.8 Fire risk map........................................................................................................................................... 37

4.9 Synthesis ................................................................................................................................................. 37

4.10 The potential for ecotourism............................................................................................................... 39

4.11 Recommendations ............................................................................................................................... 40

4.12 Suitability of methods .......................................................................................................................... 42

Literature ....................................................................................................................................... 44

Appendix ....................................................................................................................................... 46

- 1 -

1. Introduction

Background

The Seychelles are a group of 115 islands situated in the Indian Ocean between the latitudes 4° – 10° S

and longitudes 55° – 56° E and are therefore located within the tropical climate zone. They are divided

into the outer (coralline) and the inner (granitic) islands. There is evidence that the islands split from

Gondwanaland about 65 million years ago. Since then the Seychelles have been isolated from continents

and a unique vegetation has developed containing approximately 50 endemic woody species (Friedmann

1994).

Since the first human settling in 1770, many unique species of the indigenous flora are in danger of

extinction (Swabey 1970) and restricted to patches of relic vegetation. The most serious threats to the

endemic plants of the Seychelles nowadays are, besides a limited regeneration, the invasion by alien

species (Fleischmann et al. 2005) and the local extinction and habitat degradation by forest fires

(Carlström 1996). Invasive species are nonindigenous species capable of establishing and spreading

significantly within natural communities (Les et al. 1999).

A notably high abundance and diversity of endemic species can be found on glacis (Kueffer et al. 2004),

which comprise one of the most important vegetation types of the granitic islands. According to

Fleischmann et al. (2003) glacis are solitary, often monolithic rocks or parts of mountain systems, which

rise abruptly from their surroundings. They belong to the least invaded habitat types (Fleischmann

1997).

Praslin is with an area of 37km2 (Fleischmann 1997) the second largest island of the inner Seychelles

and reaches a height of 367m a.s.l. (Walsh 1984). Whereas the Seychelles are identified as a biodiversity

hotspot (Conservation International) and as a center of plant diversity (WWF and IUCN) (Fleischmann

et al. 2003), Praslin is even more special due to the sheltering of the Vallée de Mai, a UNESCO World

Heritage site. With a mean annual rainfall on Praslin (Bay Ste Anne) of about 2130mm, the climate is

slightly drier than on the other Seychelles islands (Carlström 1996).

Due to forest fires, there are considerable areas of bare erosion slopes on Praslin where often the

possibly native fern Dicranopteris l. can be found (Carlström 1996). It is a robust fern which survives well

in poor soil conditions (Russell et al. 1998). In cleared forest areas it forms large masses (Beaver 1994)

and prevents all other species from growing (Carlström 1996). Thus when establishing after a fire event

it poses a problem because it can prevent trees from regenerating and change the forest structure

(Kueffer et al. 2004). Dicranopteris l. is highly inflammable (Swabey 1970) and might increase the risk of

fire, especially during drought periods (Ikin et al. 2005). A positive aspect of a dense population of

Dicranopteris l. is its extensive root system, which can prevent soil from erosion (Beaver 1994).

The study

To prevent biodiversity-loss and for the relic vegetation to survive, a better understanding of the

interconnections between vegetation composition, tree regeneration, forest fires and the significance of

boulder fields is crucial. The privately owned area of the Fond D’Albaretz on Praslin is an ideal study

site to research those interdependencies and human impacts. The low-altitude forest of the Fond

D’Albaretz is considered an area of special conservation value (Carlström 1996). It is located in the calm

south-east of Praslin in the direct neighborhood of the Praslin Nation Park and the Fond Ferdinand

(Fig. 1), both being floristic hotspots. Two forest fires affected the Fond D’Albaretz in 2008. Over the

steep slopes of the Fond D’Albaretz, a dense network of boulder fields is spread, whose vegetation is very

similar to those of glacis (Plant Conservation Action group 2007).

Introduction

- 2 -

Fig. 1: Map of Praslin showing the study site

The Fond D’Albaretz shows an attractive potential for ecotourism and is owned by the Hotel Coco de

Mer, which aims at keeping up the biodiversity of the forest and protect endemic species by a sustainable

management of the forest. Thus alien or problematic species like Cinnamomum v., Chrysobalanus i. and

Dicranopteris l. are partly removed from time to time and replaced by endemic species. In the last years

approximately 30 nuts of Lodoicea m. and about a hundred seedlings of Deckenia n. and Nephrosperma v.

have been planted. To make use of the ecotouristic potential, a nature trail is maintained. The hotel-

guests have the possibility to visit the Jean-Baptiste Nature Trail several times a week on a guided hike.

Previous studies showed the high ecological quality of the Fond D’Albaretz (Bollier et al. 2004, Héritier

2002). A forest zoning performed by Héritier (2002) distinguished between three different forest types:

“Palm forest with rejuvenation by native species”, “broad-leafed forest with rejuvenation by native species” and

“invaded forest with rejuvenation by native species”. The relationship between boulders and vegetation was

studied by Baader & Hendry (2007) in the La Reserve area on Mahé. They showed a significant

correlation between big boulders and palms, and between small or no boulders and dicotyledonous

trees. Post-fire succession was investigated by Meuwly (2002) in the area of the Fond Ferdinand on

Praslin. Two areas were researched, one burned down in 1989 and one in 1999. Introduced species were

found to use the fire-avoiding strategy whereas native species use the fire resisting strategy and possess a

higher resprouting capacity.

So far the Fond D’Albaretz was only surveyed roughly. To obtain a good database, a more

comprehensive survey was needed. This also applies for the boulder analysis where additional aspects

like the role of boulders for threatened endemic species or the role of boulder fields as a sanctuary

protecting plants from fires can be investigated.

The hypothesis of this study is that the Fond D’Albaretz has an outstanding kind of vegetation because

it is part of a unique ecological framework, there is a lack of severe fire disturbances and human impact

and there is an extensive presence of boulder fields.

Introduction

- 3 -

To test our hypothesis, we aim at the understanding of the following scientific questions:

• What is the species composition and stand structure of the Fond D’Albaretz?

• What is the ecological value of the forest and which areas are of special interest in terms of

protection values and threatened species?

• Can the findings of Baader & Hendry (2007) regarding boulder fields and the prominent

presence of palms be confirmed?

• Are there other correlations between boulder fields and the type of vegetation (e.g. threatened

species)?

• What is the potential of the Fond D’Albaretz forest in terms of ecotourism?

• Does Dicranopteris l. influence tree regeneration and the vegetation composition?

• Is there a difference in the ecological values between the Fond D’Albaretz and his north-western

back side towards Glacis Noir?

• How is the vegetation composition affected by fire events?

• What impact do forest fires have on the succession and regeneration of native and alien plant

species?

• Which areas of the Fond D’Albaretz pose high risk to induce or spread forest fires?

• Is a lack of fire events a reason for the high ecological value of the Fond D’Albaretz?

• Do boulder fields enhance the conservation value of the study site?

Our objectives are:

• … on vegetation survey: Evaluate the stand structure, the state of species rejuvenation and the

species composition of the forest and predict future trends.

• … on the presence of boulder fields: Record the occurrence of boulder fields and the most

abundant plant species along the trails. Determine the corresponding boulder field class.

• … on zoning of the forest: Locate and validate the areas of high ecological significance with the

help of a geographic information system. Develop a forest zoning based on the following

features: (I) nativeness, (II) conservation value (III) presence of red listed plants.

• … on vegetation monitoring: Provide a detailed monitoring methodology and an extensive

database for future surveys.

• … on forest management and invasion monitoring: Give advises for the management of the

forest with a special focus on the spread of alien invasive plant species.

• … on Geographic Information System: Utilize this tool and prove that adequate use of a GIS-

based vegetation research can substantially increase the quality of vegetation surveys.

• … on general description of the burned areas: Visit the two burned areas in the Fond Ferdinand

and the two burned areas in the Fond D’Albaretz and give a general description of the state of

the areas.

• … on post-fire succession: Find out to which extent forest fires have an impact on the

occurrence and regeneration of native and alien invasive species.

• … on the mapping of boulder fields: Develop a map of boulder fields by means of interpretation

of satellite images and mapping directly in the field.

• … on mapping and evaluation the occurrence of the fern Dicranopteris l.: Record all patches of

Dicranopteris l. in the immediate vicinity of the trails within the study site.

• … on fire risk map: Develop a fire risk map for the study site by means of different parameters.

- 4 -

2. Methods

2.1 General principles

To determine the rejuvenation of species it is crucial to distinguish between different life-forms of

plants. Thus all plant-recordings are separated into the three life-forms seedlings, saplings and adults

(Tab. 1).

Tab. 1: Definition for seedling, sapling and adult according to Fleischmann (2005);

dbh: diameter at breast height (80 cm)

Dicotyledonous Trees Palms

Height dhb Leaves True stem

Seedling < 0.5m < 3cm < 100cm no

Sapling 0.5 - 2m < 3cm > 100cm no

Adult > 2m > 3cm > 100cm yes

Basis for the nomenclature are Friedmann (1994) for dicotyledonous and Robertson (1989) for

monocotyledonous plants. The red list status of endemic plants is based on Huber & Ismail (2006).

Global Positioning Service (GPS) was used in the field as a measure to obtain georeferenced data. We

used a Garmin GPSMap 60Csx, which was in any case more accurate than ± 6m. Spatial and

geostatistical analyses and mapping tasks were carried out using ArcGIS 9.2 (ESRI, Redlands, CA,

USA).

2.2 Trail transecting

The aim is to describe the present state of the forest by determining abundances, frequencies,

prominences and rejuvenation of woody plant species. Data gained by performing trail transecting

provide the basis for evaluating the conservation value of the forest and for the forest zoning. The

method is very useful to get an overview of the species composition in a forest area.

While walking along a trail, at every 2m the most abundant seedling, the closest sapling and the closest

adult tree perpendicular to the trail are recorded. The measuring-units are sub-transects of 200m, which

consist of 100 sampling-points. To describe a certain area of interest, sub-transects are summed up to

transects.

The vegetation in the study area is represented by two different transects (Fig. 2): The Jean-Baptiste

Nature Trail consisting of eight sub-transects and the expanded Nature Trail consisting as well of eight

sub-transects. For being able to study differences between the Fond D’Albaretz and the other side of the

hill transecting in two additional sub-transects along the trail towards Glacis Noir was performed (Fig.

2). A total transect length of 3.6km was covered.

Following equipment is required: Measuring tape, standardized protocol sheet, pen, GPS.

Methods

- 5 -

Fig. 2: Map of the study site showing sampling plots and trail-transects.

Data Treatment

To gain prominence values for all recorded species, the data is processed as follows. Abundance classes

(Tab. 2) based on numbers of individual species in sub-transects of 100 plant-recordings are determined

after Fleischmann (1997).

Tab. 2: Abundance-classes adopted from Fleischmann (1997)

Abundance-Class # individuals per

sampling unit

1 1

2 2-4

3 5-8

4 9-16

5 17-32

6 33-64

7 >64

The relative frequency fij of a species i within an individual sampling-plot j is calculated as:

100xn

nf

j

ij

ij = (eq. 1)

where nij is the number of sampling units in sampling-plot j having species i and nj the number of

sampling units in sampling-plot j.

Methods

- 6 -

The prominence values PVij for a species i in sampling-plot j is calculated based on the relative frequency

and the relative abundance of a certain species as:

100100 xa

a

xf

fPV

i k

ijk

k

ijk

i

ij

ij

ij

∑∑

∑

∑+= (eq. 2)

where fij is the frequency of species i in sampling-plot j and aijk the abundance class value of species i in

sampling unit k of sampling-plot j.

2.3 Count-plot analysis

The aim is to gain a plant-inventory expressed by the prominence values of the recorded species. This

method provides information on the stand structure and rejuvenation of the forest.

The sampling plots of 10x10m are divided into four sub-plots of 5x5m (Fig. 3). The northern edge of the

sampling plot is manifested by a marker tree. Starting from the marker tree, the other three edges are

determined by using a compass and a measuring tape.

Fig. 3: Schematic sketch of a sampling plot.

All plants within a sampling plot are counted and recorded according to their life-form (Tab. 1). For

every individual adult broadleaved tree, the diameter at breast height (dbh; 80cm) is measured. For trees

with more than one branch originating from the same trunk, the dbh is summed up. Due to the fact

that palms do not have a secondary growing the height of the trunk up to the point where the most

upper leaf sprouts is measured instead of the dbh. This measurement is done with a clinometer (Suunto

Oy, Finnland) which measures the angle between the ground and the desired top-point of the tree and a

measuring tape that gives the distance from the sampling point to the palm. In a next step, the height h

of palms can be calculated as:

( ) tmeasuremenhdh += )tan(* α (eq. 3)

where d is the measured distance from the tree to the sampling point, α the measured angle and hmeasurement

the height of the clinometer above ground.

0m

10m

5m

Methods

- 7 -

A total of nine permanent sampling plots with each an extent of 10x10m have been established within

the study area (Fig. 2). This leads to a total sampling area of 900m2. The marker trees of all sampling

plots are indicated with yellow plastic bands to allow a resurvey. Additionally, accurate GPS-coordinates

were recorded and sketch-maps were designed (Re. digital appendix G).

Following equipment is required: Measuring tape (25m), yardstick, plastic marker band, standardized

protocol sheet, pen, compass, GPS and clinometer.

Data Treatment

Prominence values are calculated as described in chapter 2.2. As an additional value the relative

dominance can be determined as follows.

Based on the dbh-measurements and counted adult individuals of a species, the relative dominance RDij

of species i in transect j can be calculated as:

100xa

aRD

j

ij

ij = (eq. 4)

where aji is the cumulated dbh-area of species i in sampling-plot j and aj the cumulated dbh-area of all

species in sampling-plot j.

2.4 Photo monitoring

The photo monitoring is performed as an additional measure to document the sampling plots and the

trail transects. The aim is to visually document the actual state of the vegetation. The photo monitoring

gives an insight into the species succession (growth, species recruitment and mortality) within a count

plot and along a trail transect.

Procedure when used in the trail transecting

At each start- and end point of a trail sub-transect two pictures are taken: One general view from the

middle of the transect line due south (1.3m above ground) and one picture of the ground-cover (1.3m

above ground) showing 0.25m2 at the left side of the transect line.

Procedure when used in the count-plot analysis

In every permanent plot one general view of the plot (1.3m above ground) and four ground-cover

pictures in each corner of the plot (1.3m above ground) showing 0.25m2 of the ground are taken. The

general view picture is taken in the northern edge due south giving a view over the whole plot.

The following equipment is required: Digital camera (with standardised settings), measuring tape,

compass, a 0.5m x 0.5m frame for the photo plots, protocol sheet, pen, GPS.

Methods

- 8 -

2.5 Boulder field classification

Developed by Bader & Hendry (2007) this method aims at understanding a possible connection

between the occurrence of boulder fields and palms.

To understand the possible relationship between the occurrence of boulder fields and certain plant

species a modified version of the boulder field classification according to Baader & Hendry (2007) is

performed in this study. To get a more comprehensive database, the trail transecting steps are reduced to

2m instead of 2.22m and therefore the boulder field classification is done every 10m instead of 11.1m.

The boulder field classification is performed together with trail transecting. At every 5th sampling point

(every 10m) the occurrence of boulders is estimated by recording following data: The size (length and

height) of the two main boulder-groups and the ground-coverage by boulders in percent. Additionally

the most abundant plant species (adult and sapling) are recorded. Those recordings are made

perpendicular to the trail for both sides considering a 10m-belt. According to the collected data, the

boulder classes (Tab. 3) can be determined and correlated with the plant species.

Boulder field classification is performed together with trail transecting, i.e. data was collected along a

total length of 3.2km transect-lines.

The following equipment is required: Measuring tape, standardized protocol, pen, GPS.

Data Treatment

The collected field data is classified according to the boulder-classes and the ground-cover by boulders

(Tab. 3). It is assumed that each boulder is a square of a classified size (i.e. boulder size class). If the

obtained data (height and length) do not fit within a boulder class, it was decided that the length is the

determining factor. An exception is made when the height of a boulder fits in class 5 but not the length.

In this case the boulder is classified within class 5. If two different boulder sizes are recorded but they do

not fit the same class, the bigger boulder class is decisive. The ground-cover by boulders is differentiated

between less than 50% and more than or equal to 50%.

Tab. 3: Boulder field classification according to Baader & Hendry (2007)

Class Description Cover Definition

1 Area without boulders 0 -

1a Area without boulders between bluffs of rocks 0 No boulders

2 Boulder field with small boulders ≥ 50% H: ≤ 0.5m, L: ≤ 0.5m

2a Area with a few small boulders < 50% H: ≤ 0.5m, L: ≤ 0.5m

3 Boulder field with mixed boulder sizes ≥ 50% H,L: > 0.5m and ≤ 2m

3a Area with a few different sized boulders < 50% H,L: > 0.5m and ≤ 2m

4 Boulder field with huge boulders ≥ 50% 2m < H ≤ 4m, 2m < L ≤ 8m

4a Area wiht a few huge boulders < 50% 2m < H ≤ 4m, 2m < L ≤ 8m

5 Bluffs of rock - H > 4m, L > 8m

Chi-square-Tests and Mann-Whitney-U-Tests were carried out using SPSS Statistics version 17.0 (SPSS

Inc., Chicago, Illinois, USA). Using this kind of statistics, we assessed (1) the correlations between big

boulders & palms and small or no boulders & dicotyledonous trees, (2) the correlations between

ground-coverage by boulders of more than 50% & palms and ground-coverage by boulders of less than

50% & dicotyledonous trees and (3) the correlations between big boulders & threatened species and

small or no boulders & invasive species.

Methods

- 9 -

2.6 Vegetation zoning

Based on the georeferenced data gained by trail transecting, a forest zoning is performed to locate and

validate important areas in terms of (I) nativeness, (II) protection values and (III) presence of red listed

plants.

Forest zoning based on nativeness

Forests in the Seychelles have been zonated earlier (Baader & Hendry 2007; Héritier 2002; Reinhardt &

Voellmy 2000). The zonation based on the nativeness for the Fond D’Albaretz was developed

considering those previous studies. However, adaptations for the special vegetation structure of the Fond

D’Albaretz had to be made. The aim is to get a zonation of the forest based on the present trees species

within each sub-transect. The zonation mainly distinguishes between native and invasive species. For the

group of native species a distinction is drawn between palm forest (> 50% palms) and native forest (<

50% palms). A further aspect of the zonation is the most prominently rejuvenating group of plants

(palms, native or invasive species). Nine different zones are distinguished (Fig 4): Invaded forest with

native, invasive or palm rejuvenation, native forest with native, invasive or palm rejuvenation and palm forest with

native, invasive or palm rejuvenation. The criterions are specifically described below.

First criterion: Native or invaded forest

A sub-transect is classified as being native if more than 66% of the adult trees are native species. Due to

the fact that invasive species have the ability to displace native species, a forest is classified as invaded

when more than 33% of the adult trees are invasive.

Second criterion: Palm forest or native forest

Within the study area the endemic palm species Deckenia n., Lodoicea m., Nephrosperma v.,

Phoenicophorium b. and Verschaffeltia s. are present. Especially Phoenicophorium b. and Nephrosperma v. are

highly abundant in some areas. Thus it is distinguished between palm and native forest. A forest is

classified as palm forest if more than 50% of the recorded trees are palms.

Third criterion: Native or invasive rejuvenation

Due to the high frequency of invasive saplings along some sub-transects, it is distinguished between

invasive and native rejuvenation. If more than 50% of the saplings are invasive species, the rejuvenation

of the sub-transect is declared as invasive rejuvenation.

Forth criterion: Palm or native rejuvenation

If more than 50% of the saplings are endemic palms, the rejuvenation of the sub-transect is declared as

palm rejuvenation, otherwise as native rejuvenation.

Methods

- 10 -

Fig. 4: Flowchart for the forest zoning based on nativeness

Zonation based on protection values (PtV)

The protection value provides information about the protection priority in terms of conservation of an

area. For each sub-transect (100 enumerated plants) within the study site the protection value after

Fleischmann (1997) is estimated. The ecological parameters used are (i) the diversity of natives (number

of native species per sub-transect), (ii) the singularity (number of red listed species per sub-transect based

on Huber & Ismail (2006)), (iii) the abundance of natives and (iv) invaders and (v) the regeneration

(percentage of native saplings per sub-transect). For each parameter a value between 1 and 3 is assigned

(Tab. 4). These values are entered into the matrices M1 to M3 (Fig. 5). Within M4 all the matrices are

compiled and a single value, the protection value, for each sub-transect is estimated (Fig. 6). In general,

five protection value classes are distinguished: 1, very low; 2, low; 3, medium; 4, high; 5, very high.

Methods

- 11 -

Tab. 4: Ecological parameters with the respective values.

Criterion Value

1 2 3

Diversity of natives 1 < 8 8 - 16 > 16

Singularity 2 < 5 5 - 10 > 10

Total abundance of invaders > 60 30 - 60 < 30

Total abundance of natives < 30 30 - 60 > 60

Regeneration 3 < 34 34 - 66 > 66

1 # native species, 2 # endemic species, 3 Based on an estimation of the occurrence

of native saplings

Diversity natives Abundace invaders M1

3 2 1 M2

3 2 1

3 3 3 2 3 3 3 2

2 3 2 2 2 3 2 2

Singularity

1 2 2 1 Abundance

natives

1 2 2 1

Regeneration M3 M3

3 2 1 M4

3 2 1

3 3 3 2 3 5 4 3

2 3 2 2 2 4 3 2 M2

1 2 2 1

M1

1 3 2 1

Fig. 5: The ecological status matrices M1 – M4.

Fig. 6: Combination of ecological status matrices.

Since most sub-transects within the study site show a protection value of 4, an additional validation is

made. If such a sub-transect features more than 66% endemic trees, the protection value is enhanced to

4+. If it features more than 33% invasive trees the protection value is depreciated to 4-. Thus, a more

detailed classification is obtained.

Diversity natives

Abundance invaders

Abundance natives

Singularity

Regeneration

M 2

M 1

M 3

M 4

Methods

- 12 -

Zonation based on red listed endemics

Various endemic species can be found in the area of the Fond D’Albaretz. To get an overview of the

areas with high occurrence of endemic plants a red list zonation after Baader & Hendry (2007) is

performed with one exception: A forest is classified as invaded when the invasive trees reach an

abundance of 33% instead of 50%. As a further criterion the rejuvenation by native, endemic or

invasive species is included. The red list status of the endemic species is adopted from Huber & Ismail

(2006). It is distinguished between 18 different zones. Six different zones are distinguished according to

adult trees. Each zone is then divided again into three different classes according to the amount of

rejuvenation by endemic, native and invasive species (Fig. 7). The 18 possible zones are: Invaded forest

with native, endemic or invasive rejuvenation, native forest with native, endemic or invasive rejuvenation, endemic

forest with native, endemic or invasive rejuvenation, red list status critically endangered (CR) or endangered (EN)

forest with native, endemic or invasive rejuvenation, red list status vulnerable (VU) or near threatened (NT) forest

with native, endemic or invasive rejuvenation and native forest with red list status vulnerable (VU) or near

threatened (NT) areas with native, endemic or invasive rejuvenation. The criterions are specifically described

bellow.

First criterion: Native or invaded forest

First of all it is distinguished between native or invasive vegetation. A sub-transect is classified as a native

area if more than 66% of the adult trees are native. Due to the fact that invasive species have the ability

to displace native species, a forest is classified as invaded when more than 33% of the adult trees are

invasive.

Second criterion: Native or endemic forest

As a second step it is distinguished between native and endemic areas. If more than 66% of the adult

trees are endemic, the status of the sub-transect is classified as an endemic.

Third criterion: Red list status critically endangered (CR) or endangered (EN)

As a third criterion the state of an endemic area is classified more specifically. Species owing a red list

status of CR or EN are the most threatened ones. If more than 3% of the trees belong to one of these

red list status the sub-transect is classified as CR-EN.

Forth criterion: Red list status vulnerable (VU) or near threatened (NT)

The forth criterion distinguishes between VU-NT-area and an endemic area. If more than 33% of the

endemic trees are in the red list categories VU or NT, the status of the sub-transect is classified as VU-

NT. Otherwise its status classified as an endemic area.

There are also sub-transects with less than 66% endemic trees but more than 33% categorised as VU or

NT. The status of those sub-transects is called native with VU-NT-parts.

Fifth criterion: Native or invasive rejuvenation

Based on the frequency of saplings it is distinguished between invasive and native rejuvenation. If more

than 50% of the saplings are invasive species, the rejuvenation of the sub-transect is declared as invasive

rejuvenation.

Sixth criterion: Native or endemic rejuvenation

If more than 50% of the saplings are endemic species the rejuvenation is classified as endemic

rejuvenation, otherwise as native rejuvenation.

Methods

- 13 -

Fig. 7: Flowchart for the zonation based on red listed endemics

2.7 Dicranopteris linearis survey

The aim is to get an overview of the occurrence of the fern Dicranopteris l. and to understand a possible

relationship between the occurrence of Dicranopteris l. and the kind of species composition, e.g. invasive

woody species.

While walking along trails, all Dicranopteris l. patches bigger than 1m2 and residing within or touching

the 10m-belt perpendicular on both sides to the trail are recorded. For every patch the GPS-coordinates

are taken, the extent of the area is estimated and the height of the mat is measured.

Following equipment is required: Measuring tape, standardized protocol, pen, GPS.

Data treatment

Every recorded patch is allocated to the nearest sub-transect. The total area of Dicranopteris l. per sub-

transect is calculated by summing up all patches belonging to that specific sub-transect.

A spearman correlation test was performed using SPSS Statistics version 17.0 (SPSS Inc., Chicago,

Illinois, USA). We assessed a possible correlation between the occurrence of Dicranopteris l. and the

occurrence of invasive woody species.

Methods

- 14 -

2.8 Boulder field mapping

The aim is to get an overview of the spread and structure of boulder fields within the study area. It is of

interest where individual or groups of boulders are located, what extent they have, how they are

arranged and how continuously they are.

In a first step, satellite images of the study area were interpreted to identify directly visible boulder fields.

A map was produced showing boulder fields which are not covered by dense canopy. In a second step,

this map was taken into the field to georeference boulder fields which are completely covered by canopy

and therefore not visible on satellite images. With the help of GPS those boulder fields were directly

drawn into the map. Special attention was given to the search of very long connected boulder fields. Due

to the extreme topography of the Fond D’Albaretz, it was not possible to access the complete area and to

map all boulder fields. Therefore, we distinguish between recorded features of boulder fields and assumed

features of boulder fields. Recorded features are boulder fields directly visible on satellite images or

boulder fields which were directly georeferenced in the field. Assumed features were given according to

assumed connections between large recorded features of boulder fields.

Only boulder fields with an extent of at least 10x10m and consisting of boulders fitting in class 4 or 5

according to the boulder field classification (Tab. 3) were mapped. As an additional information it was

recorded if a boulder field is covered by litter or not.

Following equipment is required: Measuring tape, standardized protocol (map to sketch boulder fields),

pen, GPS.

2.9 Qualitative monitoring of post-fire areas

Fond Ferdinand

Meuwly (2002) analyzed two areas affected by forest fires within the Fond Ferdinand, one burned in

1999 and the other in 1989. Within both areas three plots were established. Unfortunately we were not

able to relocate the exact positions of the plots due to missing plot markers and therefore no

quantitative re-survey was possible. But with help of GPS, the descriptions of Meuwly (2002) and a local

guide we were able to locate the areas where the plots are supposed to be. We then performed a

qualitative survey of those areas. The aim is to get an impression of possible changes of the vegetation

and the post-fire vegetation regeneration and succession since 2002.

The re-visit of the sites comprised an inventory of the present plant species, including the most

important grasses, the recording of the presence/absence of the fern Dicranopteris l. and estimations of

the canopy openness. In addition to this the size of bare soil and the groundcover with litter and herbs

were estimated. This estimation was made according to Braun-Blanquet (1964), considering the

adaptation made by Meuwly (2002) (Tab. 5) to allow the comparison of the values. Signs of erosion were

also recorded.

Fond D’Albaretz

Like in Fond Ferdinand, the aim of the survey is a general description of the two fire sites and the

evaluation of the state of the post-fire succession.

While surveying the burned areas we recorded the surviving species on the following criteria: (I) species

not resprouting, (II) species resprouting. The resprouting species were further classified into (a) above

ground resprouting and (b) epicormal resprouting. The last criteria was based on living vs. dead plants.

Additionally we recorded the occurrences of herbs, grasses and creepers and the size of bare soil and

litter on the ground again according to Braun-Blanquet (Tab. 5).

Methods

- 15 -

Following equipment is required: Measuring tape, standardized protocol, pen, GPS.

Tab. 5: The Braun-Blanquet coverage (1964) modified after Meuwly (2002)

BB coverage [%]

0 0-5

1 5-15

2 15-25

3 25-50

4 50-75

5 > 75

2.10 Fire risk map

This method is aiming at a visual allocation of fire risk zones, i.e. areas where fires are likely to start, and

from where they can easily spread to other areas (Jaiswal et al. 2002).

Data

In order to map fire risk zones, anthropogenic and natural (topography and vegetation) parameters have

to be regarded and included in a geographic information system. Topographic factors influencing the

spread of forest fires are slope, aspect and altitude (Castro & Chuvieco 1998; Chuvieco & Salas 1996)

because they determine microclimate and airflow. Topographic data was derived from a digital terrain

model (DTM) using the Spatial Analyst extension in ArcGIS (ESRI). Vegetation data origins from the

forest zonation described in chapter 2.6. Anthropogenic influenced localities are areas of high fire risk

because of the ignition source. Following two parameters are regarded in our analysis: Distance from

settlements and distance from roads and trails. Roads and inhabited areas were determined from

satellite pictures. Trails have been mapped during the vegetation survey using GPS. All vector-data was

converted into raster data to allow the computation of the risk values (see bellow) for individual raster-

units.

GIS-analysis

To link the continuous characteristics of the above described data to meaningful values, all parameters

were, in a first step, classified according to the risk to spread or induce forest fires (Tab. 6). In a second

step, for every class a factor was assigned, expressing the fire sensitivity by a numerical value from 1 (very

low risk) to 5 (very high risk).

Topography-based parameters are classified according to physical properties. Steep slopes lose easily

water and have a more efficient convective preheating (Xu et al. 2005), thus they catch easily fire and

spread it efficiently. Highest danger for forest fires is in dry season in the southern hemisphere winter,

which is between May and October (Walsh 1984). The altitude of the sun is around 70° in August

(Time and Date AS 2009). Therefore sunlight is most reflected on slopes facing north and least reflected

on slopes facing south. Anthropogenic influenced areas pose a high ignition risk. Thus, the risk is

decreasing with increasing distance from trails, roads and settlements. Vegetation defines the amount of

fuel available at a site and thus has a significant influence on the risk to spread or induce fire.

Methods

- 16 -

Tab. 6: Parameters influencing the risk to spread or induce fire

Parameter Weight Classes Factors Risk

Topography-based parameters

Slope 3 <10% 1 very low risk

10-25% 2 low risk

25-35% 3 medium risk

35-45% 4 high risk

>45% 5 very high risk

Aspect 1 North (316-45°) 5 very high risk

East (46-135°) 4 high risk

South (136-225°) 3 medium risk

West (226-315°) 4 high risk

Anthropogenic-based parameters

Distance to Settlements 2 <50m 5 very high risk

50-150m 4 high risk

150-300m 3 medium risk

300-500m 2 low risk

>500m 1 very low risk

2 <50m 5 very high risk

Distance to Trails and

Roads 50-100m 4 high risk

100-200m 3 medium risk

200-300m 2 low risk

>300m 1 very low risk

Fuel-based parameter

Vegetation 4 Palm forest with palm rejuvenation 5 very high risk

Native forest with palm rejuvenation 4 high risk

Native forest with native rejuvenation 3 medium risk

Invaded forest with palm rejuvenation 4 high risk

We used following equation in the GIS to determine the risk value (RV) for every individual 2x2m

raster-unit:

12

*4*2*2*1*3 VEDTDSASSLRV

++++= (eq. 5)

where SL is the classified slope, AS the classified aspect, DS the classified distance to settlements, DT the

classified distance to trails and VE the classified vegetation. Finally, a fire risk map was produced based

on RVs classified again into categories from 1 (very low risk) to 5 (very high risk). The detailed

geoprocessing-models are attached in the appendix E.

- 17 -

Fig. 8: Species composition of the

Fond D’Albaretz. Species numbers

are in brackets.

3. Results

3.1 Fond D’Albaretz - State of the forest

3.1.1 General findings

A total of 47 different plant species were found while performing

trail transecting and plot sampling (Fig. 8). Ten species (21%) are

indigenous and 21 (45%) endemic. Five (11%) introduced species

and eleven (23%) invasive species were recorded. 47 species were

enumerated by the Trail transecting method, while plot sampling

revealed only 25 species.

Five of the six endemic palm species of the Seychelles were

recorded within the study site. The palm species present in the

survey area are Deckenia n., Lodoicea m., Nephrosperma v.,

Phoenicophorium b. and Verschaffeltia s. the latter is only growing

where the conditions are more humid. The only endemic palm

species which is not present in our study site is Roscheria m., but it

can be found on the trail leading from the Fond D’Albaretz up

Glacis Noir.

3.1.2 Prominence along trail transects

Based on the PVs of adult tree species in the Fond D’Albaretz research area it has been seen that 75.4%

(PV=150.8) of all PVs attribute to native and 24.6% (PV=49.2) to alien species. 20.7% (PV=41.3) of all

PVs attribute to endemic palms. A similar pattern is found for saplings. About 76.6% (PV=153.2) of the

total PVs of saplings go to native woody species and 23.4% (PV=46.8) go to alien saplings. Palm saplings

account for 29.3% (PV=58.7) of all PVs. Regarding seedlings, the pattern is quite different. Of the total

PVs for seedlings 66.0% (PV=132.1) attribute to native and 34.0% (PV=67.9) attribute to alien species

(Fig. 9).

Fig. 9: Vegetation composition of the Fond D’Albaretz (Jean-Baptiste Nature Trail and expanded Nature Trail

together), the Jean-Baptiste Nature Trail and the expanded Nature Trail. A: Adults; Sa: Saplings; Se: Seedlings.

The most prominent adult species are the two endemic broad-leafed trees Paragenipa w. (PV=17.7) and

Pouteria o. (PV=14.1) together with the endemic palm Phoenicophorium b. (PV=17.8) (Tab. 7). Further to

that prominent species are as well Dillenia f. (PV=11.9), Canthium b. (PV=10.9), Nephrosperma v.

50%

25%

75%

0%

100%

Endemic species

(21)

Indigenous species

(10)

Alien species (5)

Invasive species (11)

25%

0%

50%

75%

100%

Fond D’Albaretz Jean-Baptiste

Nature Trail

Expanded

Nature Trail

A Sa Se A Sa Se A Sa Se

Invasive species

Alien species

Indigenous species

Endemic species

Results

- 18 -

(PV=10.6), Erythroxylum s. (PV=9.7) and Deckenia n. (PV=9.1). The most prominent invasive species in

the survey area are Cinnamomum v. (PV=11.1) and Adenanthera p. (PV=9.3).

The three most prominent adult species show also high PVs for saplings: Paragenipa w. (PV=18.2),

Pouteria o. (PV=17.6) and Phoenicophorium b. (PV=27.3). Less consistent with the prominence of adult

trees are the PVs for saplings of Deckenia n. (PV=10.7) and Canthium b. (PV=12.0). The most prominent

invasive saplings are Chrysobalanus i. (PV=16.6) and Cinnamomum v. (PV=13.5). Adenanthera p. is less

prominent, having a PV of 2.2. The most prominent seedlings are Cinnamomum v. (PV=27.3),

Phoenicophorium b. (PV=22.2) and Pouteria o. (PV=20.8).

Next to the PVs of the different species, a general trend for the future prominence is given in Tab. 7 by

comparing the PVs of adults and saplings.

Tab. 7: Prominence values of adult species and saplings recorded and their future trends. ↑: PV of saplings minus

PV of adults ≥ 2; ↗: PV of saplings minus PV of adults between 0.1 and 1.9; →: PV of saplings minus PV of adults

= 0; ↘: PV of saplings minus PV of adults between -0.1 and 1.9; ↓: PV of saplings minus PV of adults ≤ -2. The

highest PVs are marked with bold letters.

Species PV Diff. Trend Species PV Diff. Trend

A Sa A Sa

Adenanthera p.2 9.3 2.2 -7.2 ↓ Haematoxylum c. 2.8 3.3 0.5 ↗

Allophylus p. 3.2 5.6 2.4 ↑ Intsia b. 3.7 0.7 -3.0 ↓

Allophylus s.1 0.7 0.0 -0.7 ↘ Leucaena l.2 0.0 0.7 0.7 ↗

Alstonia m.2 1.1 0.0 -1.1 ↘ Lodoicea m.1 1.4 0.9 -0.5 ↘

Anacardium o.2 5.2 3.1 -2.1 ↓ Ludia m.1 2.8 1.5 -1.4 ↘

Aphloia s.1 0.0 0.7 0.7 ↗ Mangifera i. 0.0 0.7 0.7 ↗

Artocarpus a. 0.7 0.0 -0.7 ↘ Memecylon e.1 5.6 5.2 -0.4 ↘

Averrhoa b. 0.5 0.0 -0.5 ↘ Nephrosperma v.1 10.6 19.0 8.4 ↑

Bambusa v. 0.7 0.0 -0.7 ↘ Northea h.1 0.7 0.0 -0.7 ↘

Canthium b. 10.9 12.0 1.1 ↗ Ochna c.2 0.7 1.7 1.0 ↗

Calophyllum i. 5.8 5.9 0.1 ↗ Pandanus m.1 1.8 0.9 -0.8 ↘

Casuarina e.2 5.9 1.5 -4.4 ↓ Pandanus s.1 5.3 0.9 -4.4 ↓

Chrysobalanus i.2 6.8 16.6 9.8 ↑ Paragenipa w.1 17.7 18.2 0.5 ↗

Cinnamomum v.2 11.1 13.5 2.5 ↑ Phoenicophorium b.1 17.8 27.3 9.5 ↑

Clerodendrum s.2 0.5 0.0 -0.5 ↘ Pouteria o. 14.1 17.6 3.5 ↑

Craterispermum m.1 0.7 0.0 -0.7 ↘ Premna s. 0.7 0.0 -0.7 ↘

Deckenia n.1 9.1 10.7 1.6 ↗ Psidium c.2 0.5 0.0 -0.5 ↘

Dillenia f.1 11.9 7.0 -5.0 ↓ Psychotria p.1 0.0 0.7 0.7 ↗

Diospyros s.1 2.2 0.7 -1.5 ↘ Syzygium w.1 2.5 0.0 -2.5 ↓

Dracaena r. 5.1 13.2 8.1 ↑ Tabebuia p.2 3.3 3.5 0.2 ↗

Drypetes r.1 0.7 0.0 -0.7 ↘ Terminalia c. 1.2 0.0 -1.2 ↘

Erythroxylum s.1 9.7 2.2 -7.5 ↓ Verschaffeltia s.1 2.4 0.7 -1.7 ↘

Euphorbia p. 0.7 0.0 -0.7 ↘

Ficus l. 1.9 0.7 -1.2 ↘ 1 Endemic species

Gastonia c.1 0.0 0.7 0.7 ↗ 2 Invasive species

Comparison of the vegetation along the Jean-Baptiste Nature Trail and the expanded Nature Trail

In order to identify differences in the vegetation composition in terms of native and alien species the

two trails are reviewed separately. For statistical reasons, both trails comprise the same number of sub-

transects.

Results

- 19 -

For each trail 37 different species were recorded. 27 species are found along both trails. Nine invasive

and 19 endemic species are found along the Jean-Baptiste Nature Trail whereas eight invasive and 16

endemic species are found along the expanded Nature Trail. The five endemic palms growing within the

study site were recorded along both trails.

Whilst along the Jean-Baptiste Nature Trail the amount of native trees based on total PVs along this trail

is 76.2%, the amount along the expanded Nature Trail is 74.7%. Endemic species along the Jean-

Baptiste Nature Trail account for 50.3% whereas 18.4% of all adult PVs are endemic palms. Along the

expanded Nature Trail the endemics account for 53.2% whereas 22.8% are palms. The amount of

invasive species along the Jean-Baptiste Nature Trail accounts for 20.3% of all adult PVs and along the

expanded Nature Trail for 24.1%.

Generally the sapling composition (endemics, indigenous, alien, invasives and palms) is similar along

both trails.

The seedling composition along the two trails is quite different. For example the amount of invasive

seedlings based on the PVs along the Jean-Baptiste Nature Trail is 26.9% whereas along the expanded

Nature Trail the invasive seedlings account for 40.2%.

An overview of the most prominent species growing along the two trails is given in Tab. 8.

Tab. 8: Prominence Values of the 14 most prominent species along the Jean-Baptiste Nature Trail and the

expanded Nature Trail. The species are sorted by descending prominence values of adults. The highest PVs of

adults, saplings and seedlings are marked with bold letters.

Jean-Baptiste Nature Trail Expanded Nature Trail

A Sa Se A Sa Se

Paragenipa w. 1 19.6 16.9 16.5 Phoenicophorium b. 1 18.3 31.6 19.2

Phoenicophorium b. 1 17.4 23.7 24.5 Paragenipa w. 1 15.8 19.7 14.2

Pouteria o. 16.1 19.2 24.5 Cinnamomum v. 2 14.0 17.2 34.0

Dillenia f. 1 14.2 8.6 0.0 Nephrosperma v. 1 13.4 23.2 19.2

Canthium b. 12.6 15.0 20.9 Pouteria o. 12.1 15.9 16.1

Erythroxylum s. 1 12.3 1.3 1.6 Adenanthera p. 2 11.1 4.9 24.9

Deckenia n. 1 9.3 12.4 14.5 Dillenia f. 1 9.7 4.9 0.0

Cinnamomum v. 2 8.0 10.5 22.1 Canthium b. 9.2 8.3 10.3

Nephrosperma v. 1 7.7 15.4 18.5 Pandanus s. 1 9.1 2.1 0.0

Adenanthera p. 2 7.5 0.0 10.8 Deckenia n. 1 8.9 8.7 1.9

Chrysobalanus i. 2 7.1 16.2 13.3 Memecylon e. 1 8.2 5.8 7.9

Anacardium o. 2 6.8 5.6 0.0 Erythroxylum s. 1 7.1 3.3 0.0

Dracaena r. 6.4 13.9 4.8 Casuarina e. 2 6.6 0.0 0.0

Calophyllum i. 6.1 9.0 0.0 Chrysobalanus i. 2 6.5 17.2 15.0

1 Endemic species, 2 Invasive species

3.1.3 Prominence within sampling plots

A set of nine permanent sampling plots were established and investigated. Four plots are located along

the Jean-Baptiste Nature Trail and five along the expanded Nature Trail. They lay between 65 (plot I)

and 230m a. s. l. (plot C). Adult species-diversity in terms of species occurrence is lowest in plot I (ten

species) and highest in plot C and F (16 species). In average 12.7 different adult species were recorded

with a standard deviation of 2.4. Based on PVs, native species account for 100% of the adult vegetation

Results

- 20 -

in plot B and H. The lowest proportion of adult native vegetation was found in plot E with 55%. In

average, 85% of the adult vegetation is native with a standard deviation of 15%. A summary of the

results of the individual plots is given bellow. For the location of the sampling plots, refer to Fig. 2. A

general documentation of the plots is given in the digital appendix G.

Plot A

The endemic species Paragenipa w. (PV=74.5) and Phoenicophorium b. (PV=22.8) and the indigenous

Pouteria o. (PV=35) are not only dominating in their adult form but are also present as saplings and

seedlings. Together with Deckenia n. (PV=7.6) and Dillenia f. (PV=7.6) they represent 74% of all PVs of

the adult flora. The plot shows an above-average species-quantity of 14 different species of which ten are

native. Abundant and successfully rejuvenating alien species are Adenanthera p. (PV=29.7) and

Anacardium o. (PV=22.8). They are as prominent as the palm Phoenicophorium b. A lot of seedlings of

Cinnamomum v. (PV=44.1) are found but no saplings.

Plot B

Endemic species make up 92% of all PVs of the adult flora and 92% of all PVs of saplings in this plot.

Only ten different species were found, the smallest number of all plots, whereof nine species are native.

Paragenipa w. (PV=88.7) is the most prominent adult species, followed by the palms Phoenicophorium b.

(PV=54.5) and Deckenia n. (PV=31). Also present are the indigenous species Pouteria o. (PV=15.6) and

the endemic palm Nephrosperma v. (PV=10.3). All adult species found here are successfully rejuvenating.

The only alien species found is Cinnamomum v. which is only present as seedling (PV=20).

Plot C

With 16 recorded species, plot C owns the highest species-quantity of all sampling-plots. 13 species are

native whereof nine are endemic. The most prominent species is the endemic palm Phoenicophorium b.

(PV=66.1), closely followed by Paragenipa w. (PV=60). Less prominent native adult species are Canthium

b. (PV=22.4), Memecylon e. (PV=12.7), Diospyros s. (PV=9.7), Nephrosperma v. (PV=9.7) and Syzygium w.

(PV=9.7). Together, the native species constitute 95% of the adult vegetation based on PVs. Successful

rejuvenation is achieved by Paragenipa w. and Nephrosperma v. Pouteria o. is present as sapling (PV=28.6).

The sole adult alien species is Adenanthera p. (PV=9.7). It seems that it is not successfully rejuvenating

because only a few seedlings (PV=7.9) and no saplings were found.

Plot D

Based on PVs, 93% of the adult vegetation in plot D is native. With 14 recorded species, the quantity of

different species is above average. Only the two species Cinnamomum v. and Chrysobalanus i. are alien and

both of them are also invasive. Eight of the twelve native species are endemic. The highest prominence

value for adults is reached by Phoenicophorium b. (PV=53.3) followed by Nephrosperma v. (PV=34.4),

Paragenipa w. (PV=27.1), Deckenia n. (PV=17.2), Memecylon e. (PV=17.2), Canthium b. (PV=14.5), Diospyros

s. (PV=7.2), Erythroxylum s. (PV=7.2) and Pouteria o. (PV=7.2). Cinnamomum v. (PV=14.5) is the only alien

species present in its adult form. This species was also found as saplings (PV=44) and seedlings

(PV=107.8) which demonstrates the successful rejuvenation of this species. Chrysobalanus i. is

establishing because it is present as sapling (PV=40) and seedling (PV=7).

Plot E

The adult vegetation of plot E consists only to 57% of native species based on PVs. This is the lowest

share observed in all sampling plots. In addition to that, only ten different species were recorded, which

is also the lowest numbers observed. However, thereof seven are native. The clearly dominating species

in the survey area is the alien Cinnamomum v. (PV=53.7) which rejuvenates extensively. Saplings of

Cinnamomum v. make up a PV of 121.4 and seedlings a PV of 46.5. The other prominent alien species is

Adenanthera p. (PV=36.9).

Results

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The native vegetation consists of Phoenicophorium b. (PV=51.2), Nephrosperma v. (PV=37.6) and Pouteria o.

(PV20.7). Those species are rejuvenating successfully with the only exception of Nephrosperma v.

Plot F

With 16 different species recorded, plot F scores – together with plot C – the highest species-quantity.

13 out of 16 are native, whereof eight are endemic. Based on PVs, 92% of the adult vegetation is native.

Dominated by Paragenipa w. (PV=70.1) and Phoenicophorium b. (PV=52.5) the adult native vegetation

consists also of Pouteria o. (PV=26.2), Dillenia f. (PV=18.4), Dracaena f. (PV=8.2) and Erythroxylum s.

(PV=8.2). Only the two most prominent species show sufficient rejuvenation. Sole adult alien species is

Adenanthera p. (PV=16.4) which rejuvenates successfully. Cinnamomum v. (PV=19.5) and Ochna c.

(PV=3.1) are only present as seedlings.

Plot G

Made up of 72% natives (based on PVs), plot G has the second lowest share of native adult vegetation.

Twelve different species were recorded, what is bellow average. However, only the two species

Adenanthera p. and Cinnamomum v. are alien. The palms Phoenicophorium b. (PV=103) and Verschaffeltia s.

(PV=13.3) dominate the native vegetation over the less prominent species Canthium b. (PV=13.3) and

Paragenipa w. (PV=13.3). Phoenicophorium b. intensively rejuvenates and scores a PV of 150 for saplings.

Adenanthera p. (PV=30.7) and Cinnamomum v. (PV=26.5) are prominent but only Cinnamomum v. is

rejuvenating sufficiently.

Plot H

The adult vegetation is made up of only four native species, whereof two are endemic. As in plot B, no

adult alien species are present. Twelve different species were found in total, whereof four are alien.

Paragenipa w. (PV=137.8) clearly dominates the adult native vegetation over Canthium b. (PV=24),

Phoenicophorium b. (PV=20.7) and Pouteria o. (PV=17.5). In terms of saplings, Canthium b. (PV=76.2) and

Erythroxylum s. (PV=35.4) are dominating. The alien species Alstonia m. and Tabebuia p. are present as

saplings. Adenanthera p. and Cinnamomum v. are present as seedlings.

Plot I

Only ten different species are recorded, which is the lowest species-quantity observed. Seven species are

native, whereof four are endemic. Based on PVs, 82% of the adult vegetation is native.

The native adult flora consists of the endemic palm Phoenicophorium b. (PV=123.7) and the indigenous

tree species Pouteria o. (PV=40.8). Phoenicophorium b. is the only species present as saplings which leads to

a PV of 200. The adult alien vegetation comprises Adenanthera p. (PV=17.8) and Cinnamomum v.

(PV=17.8). Seedlings of Chrysobalanus i. are also recorded.

3.1.4 Red listed species

Based on prominence values, about half (51.8%) of the adult trees within the Fond D’Albaretz are

endemic. In total, 21 different endemic species are present (Tab. 9).

Two adult trees of the very rare species Drypetes r. (PV=0.7) were found within the study site, one of

them was recorded in sub-transect 1G (Fig. 2). According to Huber & Ismail (2006), this species is

classified as critically endangered (CR) and therefore the most threatened species found within the study

site. Both individuals are located within boulder fields and thus well protected. One developing seed was

found but no sign of rejuvenation.

Craterispermum m. (PV=0.7) is the only endangered (EN) species found in the survey area. Five adult

species were found in remote areas off the trails and one specimen along sub-transect 1G. They are not

located directly in boulder fields but in the vicinity of them. Five of the six discovered specimens are

Results

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located on an altitude of more than 200m a. s. l. One specimen was flowering and another one was

surrounded by a few seedlings.

The vulnerable (VU) endemic species Dillenia f. (PV=11.9) and Nephrosperma v. (PV=10.6) are quite

common. Ludia m. (PV=2.8), Syzygium w. (PV=2.5) and Verschaffeltia s. (PV=2.4) are less common and

restricted to certain areas. Ludia m. can be found at the border of boulder fields, Syzygium w. is restricted

to ridges of higher altitude and Verschaffeltia s. is present in the vicinity of rivers. 10 specimens of

Lodoicea m. were found, most of them off the trails. Only two examples of Northea h. were found, both

located in boulder fields in the vicinity of the Drypetes r. Some specimens of Allophylus s. were found,

located in shaded boulder fields.

Besides Pandanus m., all recorded species of the categories near threatened (NT) and least concern (LC)

are very abundant.

Tab. 9: Overview of the endemic species recorded within the study site by trail transecting and count-plot analysis

Species Red list classification

(Huber & Ismail, 2006)

PV

adult

PV

sapling

# adults recorded

in sampling plots

Drypetes riseleyi CR 0.7

Craterispermum microdon EN 0.7

Allophylus sechellensis VU 0.7

Aphloia theiformis var. seychellensis VU 0.7

Dillenia ferruginea VU 11.9 7.0 4

Gastonia crassa VU 0.7

Lodoicea maldivica VU 1.4 0.9

Ludia mauritiana var. sechellensis VU 2.8 1.5

Nephrosperma vanhoutteanum VU 10.6 19.0 13

Northea hornei VU 0.7

Psychotria pervillei VU 0.7

Syzygium wrightii VU 2.5 1

Verschaffeltia splendida VU 2.4 0.7 1

Deckenia nobilis NT 9.1 10.7 7

Diospyros seychellarum NT 2.2 0.7 2

Pandanus multispicatus NT 1.8 0.9

Pandanus sechellarum NT 5.3 0.9

Paragenipa wrightii NT 17.7 18.2 110

Erythroxylum sechellarum LC 9.7 2.2 2

Memecylon elaeagni LC 5.6 5.2 5

Phoenicophorium borsigianum LC 17.8 27.3 91

3.2 Boulder field classification

In total, 1289 boulder-recordings were taken. In 707 recordings (55%), no boulders were present (Fig.

10). Boulders (classes 2, 2a, 3, 3a, 4, 4a and 5) were found in 566 recordings (45%). With regard to life-

forms, in 641 (50%) of the total 1289 recordings adult individuals were found and in 648 cases (50%)

saplings.

Results

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Fig. 10: Number of recordings in each boulder class.

3.2.1 Palms vs. dicotyledonous trees

In 631 recordings (49%) the most abundant plant species were palms and in 658 recordings (51%)

dicotyledonous trees. Fig. 11 shows the correlation between boulder classes and the presence of palms

vs. dicotyledonous trees, for adults (a) and saplings (b).

Fig. 11: Comparison between the numbers of recordings of palms vs. dicotyledonous trees for each boulder class.

(a) is showing adult trees and (b) saplings.

1. Correlation between boulder classes and the presence of palms and dicotyledonous tree species

In order to be able to compare the boulder classification by Baader & Hendry (2007) in the La Reserve

Forest on Mahé with the results of the Fond D’Albaretz Forest, the set of boulder classes was simplified

to five classes. Subclasses were added to their main classes (e.g. 3a to 3) and subclass 1a was added to

class 5.

Adult palms show a significantly higher correlation with the presence of big boulders than adult

dicotyledonous trees. The mean boulder class for adult palms is 3.03 and the mean boulder class for

adult dicotyledonous tree species is 1.81 (Chi-square-Test, p<0.001, chi-square-value=113.829; Mann-

Whitney-U-Test, p<0.001).

Results

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A similar pattern can be observed for palm-saplings and dicotyledonous tree saplings. The mean boulder

class for palm-saplings is 2.32 and the mean boulder class for dicotyledonous tree saplings is 2.01 (Chi-

square-Test, p=0.055, chi-square-value=9.246; Mann-Whitney-U-Test, p=0.007).

2. Correlation between ≥ 50% ground-coverage by boulders and the presence of palms and dicotyledonous trees

The boulder classes 1, 1a, 2a, 3a and 4a were aggregated to the class “< 50%” and the boulder classes 2,

3, 4 and 5 to the class “≥ 50%”.

The presence of adult palms shows a significantly higher correlation with the occurrence of ≥ 50%

ground-coverage by boulders than the presence of adult dicotyledonous trees (Chi-square-Test, p<0.001,

chi-square-value=38.784; Mann-Whitney-U-Test, p<0.001).

A significantly higher correlation with the presence of boulders covering more than 50% of the ground

can also be observed for palm-saplings (Chi-square-Test, p=0.003, chi-square-value=8.915; Mann-

Whitney-U-Test, p<0.001).

3.2.2 Threatened species vs. invasive species

In 389 cases of the total 1289 boulder-recordings, threatened (red list status CR, EN and VU) or

invasive species were recorded. The histogram is shown in Fig. 12.

Fig. 12: Comparison between the numbers of recordings of threatened species vs. invasive species for each boulder

class.

Correlation between the presence of big boulders and the presence of threatened versus invasive species

Boulder-classes were simplified to five classes. Subclasses were added to their main classes (e.g. 3a to 3)

and subclass 1a was added to class 5.

Comparing red-listed species with alien invasive species, the Mann-Whitney-U-Test finds moderate

evidence (p=0.054) that the presence of threatened species (adults and saplings) shows a better

correlation to the presence of big boulders. However, the Chi-square-Test shows no evidence (p=0.202,

chi-square-value=5.959). The mean boulder class for threatened species is 2.31 and the mean boulder

class for invasive species is 2.03.

Results

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3.3. Vegetation zoning

Forest Zoning

The dominating forest type is native forest with palm rejuvenation (ten out of sixteen sub-transects) (Fig.

13a). In total, four distinguished forest zones are found. Along the Jean-Baptiste Nature Trail all sub-

transects are classified as native forest whereof three show native rejuvenation and five palm

rejuvenation. The expanded Nature Trail is dominated by native forest with palm rejuvenation too (five

sub-transects). However, two sub-transects (2C and 2D) are classified as palm forest with palm

rejuvenation and one (2E) as invaded forest with palm rejuvenation.

Vegetation zoning according to the red list status

Eight of sixteen sub-transects are classified as VU-NT-area with endemic rejuvenation, which is the most

prominent vegetation-class (Fig. 13b). Seven different zones were found. Four sub-transects are classified

as native area with VU-NT-parts, two of it with native and two with endemic rejuvenation. There is one

sub-transect (1G) classified as CR-EN-area along the Jean-Baptiste Nature Trail. Along this sub-transect

an adult Drypetes r. (CR) was recorded. Two sub-transects are classified as native area, one with endemic

and one with native rejuvenation. The only sub-transect (2E) classified as an invaded area was found

along the expanded Nature Trail. However, the rejuvenation of sub-transect 2E is endemic.

Vegetation zoning according to Protection Values

In general, the study site shows high to very high protection values (Fig. 13c). Within the study area of

the Fond D’Albaretz 15 of 16 sub-transects have a protection value of 4 (high), whereof eight sub-

transects gained the appreciation to 4+ and only one (2E) the depreciation to 4-. The highest protection

value of 5 is only found in sub-transect 2B.

Fig. 13: Vegetation zonation maps for the Fond D’Albaretz area, with respect to (a) the type of forest = forest zoning,

(b) the IUCN status of occurring red listed plant species = red list zoning and (c) the need to protect the area due of

its ecological value = protection value zoning.

Results

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3.4 Correlation between Dicranopteris l. and invasive species

The total area occupied by Dicranopteris l. in the immediate vicinity of the three trails is estimated to be

8640m2. The spatial allocation to the individual sub-transects is shown in Tab. 10. The average area

covered by Dicranopteris l. per sub-transect is 480m2 with a standard deviation of 565m2. The abundance

of invaders is determined with the data gained by trail transecting.

Tab. 10: Abundance of invaders and Dicranopteris l. area per sub-transect.

Sub-Transect Abundance of invaders Dicranopteris l. Area

[%] [m2]

1A 32.5 1

1B 20.5 160

1C 20.5 300

1D 11.4 769

1E 19.5 15

1F 12.2 109

1G 12.8 273

1H 7.3 134

2A 16.7 600

2B 20.0 2054

2C 25.7 0

2D 20.0 4

2E 30.6 30

2F 22.2 885

2G 25.6 320

2H 23.8 536

3A 25.0 1316

3B 34.2 1134

No correlation between the occurrence of Dicranopteris l. and the abundance of invasive species in the

vicinity of the Dicranopteris dominated areas was found (two-sided Spearman-correlation, p=0.883).

However, along transect 3 there was a significantly larger area of Dicranopteris l. per sub-transect found

than along transect 1 (t-Test, p=0.001).

Results

- 27 -

3.5 Occurrence of boulder fields

A total area of 46’437m2 boulder fields was mapped. Most of the boulder fields were actually recorded

or checked in the field whereas only a small part was assumed (Fig. 14). It is striking to see that boulder

fields are strongly linked to each other and that they obviously fragment the forest.

Fig. 14: Map of recorded and assumed boulder fields within the study area.

3.6 Qualitative monitoring of post-fire areas

All areas have been visited in November 2008.

Fond D’Albaretz: General description of the burned area in May 2008

Due to the fire event, the area is spread with dead trunks. However, some species were able to either

survive (without resprouting) or to re-grow (resproute) after the fire event (Tab. 11). Especially

individuals of Lodoicea m. and also Phoenicophorium b. and Deckenia n. were able to survive best after the

fire. For Phoenicophorium b. and Deckenia n. also resprouting was often observed. There is a lot of bare

soil present (>75%) and grasses, herbs and creepers are starting to establish themselves. The ground is to

15-25% covered with leaf litter. Only few alien species are growing in the burned area, one of it being

the invasive Clerodendrum s. However, no Adenanthera p. seedlings, as was expected, were found. The

estimated canopy openness is 76-100%.

Fond D’Albaretz: General description of the burned area in September 2008

A lot of plants have died during the fire. Dead trunks are spread all over the area. Some plants survived

or were able to re-grow (resprouts) after the fire event (Tab. 11). In November 2008, a few species, e.g.

Phoenicophorium b., were already resprouting. Only few grasses and no creepers and herbs were present in

Results

- 28 -

the burned area. There was a lot of bare soil present (50-75%) but in some areas the ground was almost

totally covered with leaf litter (25-50%). Along the eastern border of the burned area a lot of seedlings of

the species Paragenipa w., Pouteria o., Phoenicophorium b., Cinnamomum v. and Adenanthera p. were

establishing and considerable amounts of Adenanthera p. seeds were found. The canopy openness was 51-

75% whereas a lot of leafs building the canopy were dead. The fire also burned a small part of the Jean-

Baptiste Nature Trail (Fig. 2). To enhance the regeneration of this area, about 630 seedlings of different

indigenous and endemic species have been planted in October 2008. Most of them were doing fine in

November 2008 aside from Canthium b. A detailed list of the re-introduced planted species is attached in

the appendix F.

Tab. 11: Overview of the recorded species and their state within the two burned areas in the Fond D’Albaretz

Surviving species Resprouting species Barely never

surviving Other species

above ground

resprouting epicormic shoots

Casuarina e.2 Adenanthera p.2 Anacardium o.2 Canthium b. Clerodendrum s.2

Chrysobalanus i.2 Anacardium o.2 Dillenia f.1 Curculigo r.1

Deckenia n.1 Cinnamomum v.2 Erythroxylum s.1 Flagellaria i.

Dillenia f.1 Deckenia n.1 Pouteria o. Passiflora s.

Lodoicea m.1 Dillenia f.1 Syzygium w.1 Scleria s.

Paragenipa w.1 Dracaena r. Stachytarpheta j.

Phoenicophorium b.1 Haematoxylum c. Turnera u.

Syzygium w.1 Intsia b.

Lodoicea m.1

Paragenipa w.1

Phoenicophorium b.1

Pouteria o.

Burned in M

ay 08

Syzygium w.1

Chrysobalanus i.2 Nephrosperma v.1 Erythroxylum s.1 Canthium b. Curculigo r.1

Deckenia n.1 Paragenipa w.1 Pouteria o. Pandanus m.1 Flagellaria i.

Dillenia f.1 Phoenicophorium b.1

Paragenipa w.1 Pouteria o.

Phoenicophorium b.1

Syzygium w.1 Burned in Sept. 08

1 Endemic, 2 Invasive

Fond Ferdinand: General description of the burned area in 1989

On-site of plot 7, on the top of a ridge, a lot of bare soil is visible (15-25%) and the ground is heavily

affected by soil erosion. Further down the hillside, at plot 9, erosion plays only a minor role and at plot

8 in the valley, no sign of erosion was observed. In areas affected by erosion the vegetation is generally

less dense. Within the whole area a lot of Lophoschoenus h. is growing and at plot 8 and 9 an even bigger

variety of species of herbs and grasses was recorded.

Adult trees are mostly arranged in vegetation patches. On top of the ridge those patches are separated by

areas of eroded soil whereas further down the hillside they are more and more linked to each other by

belts of herbs and grasses. Due to the fact that there is no closed vegetation, there is also no closed

canopy and the canopy openness is between 76-100%. In the whole area only few saplings and seedlings

are present, mostly within or next to the vegetation patches. The ground-cover with leaf litter is about 5-

15%. The trees on top of the ridge are growing very slowly and are quite small, whereas the trees further

Results

- 29 -

down the hillside are doing much better and are taller. To enhance regeneration of the vegetation the

two alien species Acacia m. and Acacia p. were planted. They were doing very well in November 2008.

There is also Dicranopteris l. present on-site of plot 7. An overview on the recorded species is given in

Tab. 12.

Fond Ferdinand: General description of the burned area in 1999

The ground is mostly covered with leaf litter (50-75%) and only little bare soil is visible (15-25%). A lot

of Lophoschoenus h. and Costularia f. was observed. Curculigo r. and Flagellaria i. are present in a less

extensively. Almost no herbs were seen. To improve tree regeneration Acacia m. and Acacia p. were

planted, producing most of the litter covering the ground. On-site of plot 3 it looks a bit different. Due

to the fact that this area is very exposed, a lot of bare soil is present and sings of erosion are visible. Only

few Acacia sp. were planted. Even though the Acacia sp. and also some indigenous species are growing

well, there is a canopy openness of 76-100% and therefore no closed canopy. At plot 1 and 2 the canopy

openness is between 51-75%. The whole area comprises only few juveniles, most of them being

Phoenicophorium b. and Deckenia n. A lot of Acacia sp. seeds are spread on the ground but only few

seedlings are establishing. Dicranopteris l. was only recorded in small patches. An overview on the species

recorded is given in Tab. 12. Around plot 3 Aspargus s. is growing. The area of plot 2 was cleared from

the invasive Chrysobalanus i. However, in November 2008 it was already coming back (personal

communication with Micheal Gill, Praslin, 2008). On the hillside, erosion-barriers were constructed

with wood from cleared Tabebuia p. trees. These barriers prevent erosion and stabilize the soil to support

reforestation in steep slopes.

Tab. 12: List of the woody species of the areas burned in 1989 and 1999 in the Fond Ferdinand

Area burned in 1989

(Plots 7, 8, 9)

Area burned in 1999

(Plots 1, 2, 3)

Acacia m.2, P Erythroxylum s.1 Acacia m.2, P Nephrosperma v.1

Acacia p.2, P Intsia b. Acacia p.2, P Pandanus m.1

Adenanthera p.2 Lodoicea m.1 Anacardium o.2 Paragenipa w.1

Alstonia m.2 Nephrosperma v.1 Canthium b. Phoenicophorium b.1

Canthium b. Paragenipa w.1 Casuarina e.2 Syzygium w.1

Casuarina e.2 Phoenicophorium b.1 Cinnamomum v.2, S Tabebuia p.2

Chrysobalanus i.2 Pouteria o. Chrysobalanus i.2

Deckenia n.1 Scaevola s. Deckenia n.1

Dillenia f.1 Syzygium w.1 Dillenia f.1

Dodonaea v. Tabebuia p.2 Dodonaea v.

Dracaena r. Intsia b.

1 Endemic, 2 Invasive, P Planted, S Only seedlings

Results

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3.7 Fire risk map

The first fire risk map (Fig. 15) produced in the Seychelles clearly demonstrates a high fire risk in the

whole area of the Fond D’Albaretz. Due to the steep slopes, the availability of trails and the excessively

present fuel most of the areas investigated exhibit a high risk for the spread or the induction of fire. A

very high risk is only found in steep areas very near to trails, the main-road and to settlements. Medium

risk is restricted to flatter areas on ridges or in valleys. Low risk areas are very confined and are only

found on plateaus in great distance to trails. No very low risk areas were found.

Fig. 15: Fire Risk Map of the Fond D’Albaretz visualizing the risk to spread or induce fire.

Results

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3.8 Trail towards Glacis Noir - State of the forest

3.8.1 Prominence along trail transects

Along the two sub-transects of the Glacis Noir Trail, 19 different species were recorded. Two species are

indigenous, twelve endemic and five invasive. Based on PVs of adult tree species, 70.4% of all PVs

attribute to native and 29.6% attribute to invasive species. In terms of saplings 73.5% attribute to native

and 26.5% attribute to invasive species. Regarding seedlings 61.0% is accredited to native and 39.9%

accredited to invasive species. The most prominent species along the Glacis Noir Trail are Paragenipa w.

(PV=20.2), Nephrosperma v. (PV=18.9) and the invasive Chrysobalanus i. (PV=20.2). Further species are

Canthium b. (PV=15.5), Deckenia n. (PV=13.8), Dillenia f. (PV=13.8), Memecylon e. (PV=12.5) and

Phoenicophorium b. (PV=15.1). Next to Chrysobalanus i., the alien species Casuarina e. (PV=12.5) and

Cinnamomum v. (PV=15.1) are also very common. The most prominent sapling species is Chrysobalanus i.

with a PV of 34.5 followed by Phoenicophorium b. (PV=30.5). The most prominent seedling species are

Cinnamomum v. (PV=34.7) and Chrysobalanus i. (PV=32.5).

3.8.2 Vegetation zoning

Forest Zoning

One sub-transect is classified as native forest and one as invaded forest (Fig. 16a). Both sub-transects

show a rejuvenation dominated by invasive species.

Vegetation zoning according to the red list status

Sub-transect 3A is classified as valuable VU-NT-area whereas sub-transect 3B is classified as an invaded

area (Fig. 16b). Both sub-transects again show invasive rejuvenation.

Vegetation zoning according to Protection Values

The two sub-transects along the Glacis Noir Trail show high protection values (Fig. 16c). Sub-transect 3A

obtained an appreciation to 4+ and sub-transect 3B a depreciation to 4-.

Fig. 16: Vegetation zonation maps for the trail towards Glacis Noir, with respect to (a) the type of forest = forest

zoning, (b) the IUCN status of occurring red listed plant species = red list zoning and (c) the need to protect the area

due of its ecological value = protection value zoning.

- 32 -

4. Discussion and conclusions

4.1 Species composition

The quantitative results show that the vegetation of the Fond D’Albaretz is to a great extent dominated

by endemic species whereof the most prominent ones are Phoenicophorium b. and Paragenipa w. About

half of all individual endemic trees recorded were palms. Indigenous species represent one forth,

whereas Pouteria o. is the most dominating species. Alien species account for only a small amount of the

recorded trees, whereas the invasives account also for about one forth. The most dominating invasive

species are Cinnamomum v. and Adenanthera p. In terms of seedlings, invasive species account for about

one third. Especially Cinnamomum v. and also Adenanthera p. are very common. However, prominence

values of saplings and adults reveal clearly that only very few are actually able to grow up.

A comparison with the Vallée de Mai (Tab. 13) shows that the Fond D’Albaretz has a quite high tree

density. With a look at the palm density one can see that in both areas a high amount of trees are palm

species, in the Vallée de Mai slightly more than in the Fond D’Albaretz. Whereas the tree density is

higher, a very low species regeneration is generally found in the Fond D’Albaretz compared with the

Vallée de Mai. What comes along with a higher tree density is a lower light intensity on the ground

which might influence species recruitment. Under reduced light conditions it is getting harder for new

seedlings to establish. Thus the lower regeneration might be explained by the light climate, although

Fleischmann et al. (2005) could not find any correlation between the light climate and a possible

influence on the regeneration. Since the tree density within the Fond D’Albaretz is a factor of three

higher we think that it might be reasonable that the reduced light conditions on the ground might have

an influence on the regeneration. However, further research with a broader range of tree densities would

be needed.

Tab. 13: Tree density and regeneration within the Fond D’Albaretz and the Vallée de Mai

Fond D'Albaretz Vallée de Mai (1998)*

Mean SE Mean SE

Total tree density (ha-1) 3411 961 1271 343

Total palm density (ha-1) 1244 613 646 119

Total regeneration (saplings/tree) 0.3 0.1 1.2 0.4

Palm regeneration (saplings/tree) 0.3 0.2 2.0 0.8

*Data from Fleischmann et al., 2005

The high amount of native species is also visible in the forest zoning where only one out of 16 sub-

transects was classified as invaded forest. All others were classified as native or palm forest. This finding

characterises the Fond D’Albaretz by definition as a “native and palm forest area”.

The vegetation of the Jean-Baptiste Nature Trail was zoned by Héritier in 2002. Five sub-transects were

classified as broad-leafed forest, two as palm forest and one as invaded forest, all with rejuvenation by

native species. Our study classified all those sub-transects as native forest. To some extent, the shift of

this classification is caused by the different zoning criterions. Héritier (2002) classified the forest (broad-

leafed and palm forest) according to the most frequent tree species whereas our study classified

according to the abundance of native and palm species. If we had used Héritier’s classification, some

transect would have been classified as palm forest, event though they comprise more than 50% native

non-palm species. Thus, our approach seems more suitable for a general classification whereas Héritier’s

approach seems more suitable to classify according to the most frequent species. The criterion for

invasive forests was the same for both studies. Another cause which contributes to this inconsistency in

Discussion and conclusions

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classification is possibility the selection of different starting points of the sub-transects. The sub-transect

classified as “invaded forest” by Héritier (2002) is quite close to a settlement. There the human impact

provides more habitats for invaders and also some invasive fruit trees are planted. Thus it seems

reasonable that by a shift of the starting point more invasive species were recorded by Héritier (2002).

Another possibility, next to those methodological reasons, is that due to an active site management, like

clearing of invasive species (personal communication Matthieu LaBuschagne 2008), the prominence of

invaders might have decreased and thus the native vegetation composition may have improved since

2002.

With only one sub-transect classified as “invaded forest” and none with the classification “invasive

rejuvenation”, the study site does not seem to be heavily invaded with alien plant species. If we consider

that in the direct neighbourhood of the Fond D’Albaretz, several sub-transects within the area of the

Fond Ferdinand and up to Glacis Noir were classified as “invaded forest with rejuvenation of invasive species”

(Héritier 2002) and also in the Praslin National Park several sub-transects were classified as “invaded

forest“ (Reinhardt et al. 2000), the Fond D’Albaretz study site shows a relative low prominence of

invasive species. Also with respect to the forest succession and species rejuvenation it is presumed that

also in the future the forest will be dominated by native and especially endemic species.

4.2 Ecological value

The zonation based on protection values clearly revealed the high ecological value of the Fond

D’Albaretz. This finding is supported by the high mean protection value of 4.1 and the fact that the

lowest protection value of 4- was only assigned once. All other sub-transect have a PtV of four or higher.

By comparing the Fond D’Albaretz with the Vallée de Mai (Tab. 14), we want to highlight the

importance of the Fond D’Albaretz in terms of its ecological importance on a broader scale. The Vallée

de Mai is an area of high ecological importance and due to its status as a World Heritage Site by

UNESCO (Fleischmann et al. 2005) a good reference for a comparison. The protection values of the

two compared sites are on a comparable high level. The Fond D’Albaretz comprises one sub-transect

classified with a PtV of 5, whereas the Vallée de Mai only comprises sub-transects with PtVs of 4. The

total abundance of native species is slightly higher for the Vallée de Mai whereas the share of native

species is slightly higher for the Fond D’Albaretz. The state of singularity can not be compared due to

the different number of sub-transects performed. However, if we consider a typical species increase with

an increasing area, the singularities in both areas are on a similar level. The comparison between the

Fond D’Albaretz and the Vallée de Mai shows that the ecological value of the Fond D’Albaretz in terms

of protections values and abundances of native species is absolutely comparable to the values of the

Vallée de Mai.

Tab. 14: Comparison of the Fond D’Albaretz with the Vallée de Mai.

Protection

value

Abundance

native species

Native share of

species diversity Singularity2

Number of

Transects

Fond D'Albaretz 4.1 77.9 % 66.0 % 21 16

Vallée de Mai 1 4.0 88.1 % 57.5 % 14 7

1 Data from Reinhardt & Voellmy (2000) 2 Red list species according to Procter (1974)

It is quite striking to see how the so called “red list zonation” parallels the high ecological value of the

Fond D’Albaretz area. It is a habitat which harbours a lot of threatened species. Most of the area

contains a significant amount of species classified as VU or NT. And there are also species present

Discussion and conclusions

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classified as CR or EN. For example the very rare Drypetes r. which suffered from exploitation and

habitat loss (Carlström 1996, Friedmann 1994) enjoys a relatively well conserved habitat.

The Fond D’Albaretz ranges from sea-level to a height of 250m a.s.l. The original flora of this height

before human exploitation is described in the literature (Friedmann 1987, Vesey-Fitzgerald 1940). This

low altitude forest comprised a typical plant community dominated by endemic palms (Deckenia n.,

Nephrosperma v., Phoenicophorium b.) and nowadays rare species like Craterispermum m., Dillenia f., Drypetes

r. or Medusagyne o. Due to timber-exploitation and the extension of settlement-areas, these days only

relics of this original vegetation composition can be found. Parts of the Fond D’Albaretz are indeed such

relics, e.g. the western part of the Jean-Baptiste Nature Trail or the northern part of the expanded

Nature Trail. The plant composition of those regions is very similar to the original vegetation in terms of

high endemism, the presence of rare species and the low abundance of alien species.

In summary three lines of evidence clearly demonstrate the ecological importance of the Fond

D’Albaretz: (1) A consistently high protection value was found over the whole study area, (2) a

comparison with the Vallée de Mai revealed similar high levels of ecological values and (3) relics of low-

altitude forest were identified.

4.3 The role of boulder fields

A characteristic feature of the granitic island of the Seychelles is the presence of boulder fields. Those

accumulations of granitic rocks of different shapes and sizes produce a special reserve for plant species.

The cumulative existence of very rare species in boulder fields is well documented in the literature

(Fleischmann et al. 1996, Procter 1984) but not fully understood yet. Our study offers a contribution to

better understand the dynamics of boulder fields.

Baader & Hendry (2007) give statistical evidence that endemic palms establish and grow better between

big boulders and in boulder fields, whereas dicotyledonous trees rather occur between small boulders or

in areas without boulders. Concerning the presence/absence of boulders, to their knowledge this was

the first study which associates the geomorphic characteristics of a site with the vegetation structure. We

were now able to confirm those findings with a more extensive database. In addition to that, we were

also able to prove statistically that endemic palms establish and grow better in areas where boulders

cover 50% or more of the ground, whereas dicotyledonous trees prefer areas with a coverage of less than

50%. Obviously those two findings are closely related: In the Seychelles it seems that endemic palms are

adapted to the special conditions of boulder fields. The more and the bigger the boulders, the higher is

also the coverage by boulders.

Concerning threatened species, we found an indication that they establish and grow better between big

boulders and in boulder fields than do invasive species. However, this indication is only based on a

probability of a P-value near 0.05. This possible correlation could be caused by the adaptation of

threatened species to extreme conditions in boulder fields such as temperatures exceeding 50° C or

relative humidity dropping below 30% (Fleischmann et al. 1996). Due to the uniqueness of boulder

fields and evolutionary reasons, invasive species do not have such an adaption and are not able to

compete with the well adapted endemic (mostly threatened) species.

4.4 Future trends

In general, more or less stable population structures of endemic, native, alien and invasive trees can be

predicted in future. However, a shift in prominence values of individual species within the group of

endemic, native, alien and invasive species is likely. One expected shift concerns the group of endemic

species: For the future vegetation of the Fond D’Albaretz it seems feasible that this group will be

Discussion and conclusions

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dominated even more by palms, especially by Phoenicophorium b. and Nephrosperma v. which show high

PVs for saplings, and less by endemic broad-leafed trees. This trend is also supported by the findings of

forest zoning where most sub-transects are classified as “forest with palm rejuvenation”. Deckenia n. also

shows an increasing trend in prominence, whereas the two palms Lodoicea m. and Verschaffeltia s. will

probably decrease their prominence, since their rejuvenation is not sufficient. Most of the other

endemic species show a decreasing trend. Some of them are very rare and sometimes no saplings were

recorded at all. The endemic Paragenipa w. will still be very prominent in the future. For the alien

species, no big changes are expected. Within the group of invasive species it seems likely that

Chrysobalanus i. and Cinnamomum v., will increase their prominence, whereas other species like

Adenanthera p. will rather decrease.

The Fond D’Albaretz forest will have stable shares of native and alien vegetation. Changes are only

suggested within vegetation classes, e.g. palms will increase their prominence within the class of endemic

species.

4.5 Dicranopteris l. and the abundance of invasive species

Statistical tests could not prove a correlation between the occurrence of Dicranopteris l. and the

abundance of invasive species. Dicranopteris l. is an efficient invader on disturbed and eroded areas

(Carlström 1996). It is able to effectively build a dense ground-coverage so that no seedlings of other

species can establish. Needless to say this includes invasive as well as native species. But concerning the

occurrence of alien species, this could be one of the reasons why no correlation between the occurrence

of Dicranopteris l. and the abundance of invasive species could be found.

However, we qualitatively observed that when the dense mat of Dicranopteris l. is unravelled for construct

a trail, juveniles of typically invasive species like Chrysobalanus i. or Tabebuia p. are able to establish

themselves. Endemic species are probably not able to compete with those species in such sites. Therefore

it is crucial to avoid the development of large Dicranopteris l. mats because they impair the regeneration

of the former forest after a disturbance and the rehabilitation of infested areas is extremely difficult.

4.6 Comparison of the Fond D’Albaretz with the adjacent area towards Glacis Noir

The main slopes of Fond D’Albaretz are directed towards south and south-west. For being able to

compare this side of the Fond D’Albaretz with its northern extensions towards Glacis Noir, vegetation

data along the trail towards Glacis Noir was collected.

Along the trail towards Glacis Noir, slightly higher abundances of invasive species were recorded.

Especially Chrysobalanus i. is a very abundant species in this region. The forest zonation reveals a

remarkable difference between the two sides: Both sub-transects along the Glacis Noir Trail show an

“invasive rejuvenation” dominated by invasive species whereas in the Fond D’Albaretz area no sub-transect

shows rejuvenation dominated by invasive alien tree species. However, in terms of protection values, the

two sides are comparable. But due to the high abundance of invasive saplings, this could change in

future. One of the two sub-transects is already classified as “invaded forest” and because of the invasive

rejuvenation the adult vegetation will certainly be more dominated by invasives in future.

Another striking difference between the two sides is the presence of areas infested by Dicranopteris l. The

back side of Fond D’Albaretz towards Glacis Noir comprises significantly bigger areas of Dicranopteris l.

per sub-transect than along the Jean-Baptist Nature Trail. This leads to the assumption that here, in

comparison to the core of the Fond D’Albaretz area, more disturbances, most probably fire events, have

occurred in the past which favoured the infestation by Dicranopteris l. Large patches of such post-

disturbance-areas can be seen along the trail towards Glacis Noir, they are composed of a typical plant

community dominated by Dicranopteris l. and Chrysobalanus i.

Discussion and conclusions

- 36 -

4.7 Post fire regeneration

Fond D’Albaretz

Within five months two fires affected the Fond D’Albaretz area. It is obvious to see in our results (Tab.

15) that the area burned in May had five months more to evolve than the area burned in September in

such a way that the ground-cover comprising mainly herbs and grasses is better developed. Besides this,

more species have already started to resprout. The proportion of bare and exposed soil is bigger because

most of the leaf litter is already decomposed and eroded. The canopy is much more open because all

dead trees lost their leaves already whereas in the area burned in September, the dead leafs still hold on

to the trees.

Tab. 15: Comparison of the qualitatively estimated ground cover with herbs and grasses, leaf litter and bare soil

after Braun-Blanquet adapted by Meuwly (2002) and the canopy openness of the two burned areas within or next

to the Fond D’Albaretz in May and September respectively.

Herbs and

grasses (BB)

Bare soil

(BB)

Leaf litter

(BB)

canopy

openness %

Fond D'Albaretz (May) 1 5 2 76-100

Fond D'Albaretz (Sept.) 0 4 3 51-75

Most of the surviving or resprouting species are endemic (palms and broad-leafed trees). This finding

agrees with reports by Meuwly (2002) and observations by Fleischmann after a fire on Mt. Capucin,

Mahé in 1994 (personal communication Karl Fleischmann 2009). Based on this data we presume that

the capacity of resprouting after a fire is higher by endemic species compared to introduced taxa. If this

assumption proves right the data would provide one more link between the Seychelles endemics and a

typical fire adapted Gondwanaland vegetation.

Fond Ferdinand: Comparison with the observations of Meuwly (2002)

Since Meuwly’s visit in 2002 of the area burned in 1989, the ground-cover with leaf litter has decreased,

the ground-cover with herbs remained more or less the same and there is also about the same amount of

bare soil present (Tab. 16). On the steep hillside near the top of the ridge the vegetation is in an even

worse condition than in 2002. The building of erosion barriers, like they were built in the area burned

in 1999, might help to reduce soil erosion.

Within the area burned in 1999 less bare soil was recorded in 2008 than in 2002 (Meuwly) whereas the

leaf litter cover and the ground-cover with herbs and grasses increased (Tab. 16). Direct signs of fire

disturbances, e.g. burned trees, cannot be seen anymore. But there are several trees which survived the

fire and show fire marks like fire scars on the stem.

Tab. 16: Ground cover with herbs and grasses, leaf litter and bare soil after Braun-Blanquet adapted by Meuwly

(2002) of the two areas burned in the Fond Ferdinand in 1989 and 1999 respectively.

Herbs and

grasses (BB)

Bare soil

(BB)

Leaf litter

(BB)

Fond Ferdinand 1989 (visited 2002) 2 2 3

Fond Ferdinand 1989 (visited 2008) 2 2 1

Fond Ferdinand 1999 (visited 2002) 0 3 1

Fond Ferdinand 1999 (visited 2008) 1 1 4

Based on the vegetation density and ecosystem diversity of the area burned in 1989, a recovery time after

a fire disturbance more than 10 years was determined by Meuwly (2002). But he also mentioned that the

Discussion and conclusions

- 37 -

recovery is heavily dependent on the specific site characteristics. Our observations in the area burned in

1989 confirmed this hypothesis. Whereas in the areas of the two plots located further down the hillside

the vegetation seems to recover successfully, the area of the plot on top of the ridge shows still a high

amount of bare soil and erosion prevents the vegetation-patches to properly link to each other. It seems

likely that in steep areas recovery takes longer due to a more intense soil erosion. The construction of

erosion barriers or planting of suitable species could help to enhance regeneration. Such suitable species

could be soil stabilizer like the two sedges Lophoschoenus h. and Costularia f. A further promising species

to plant is Phoenicophorium b. because of its enormous phenotypic plasticity and its high litter

production.

The species compositions of the two burned areas within the Fond Ferdinand have not changed since

2002 except for the presence of Dicranopteris l.: Meuwly (2002) does not mention any Dicranopteris l.,

whereas we recorded various patches. The two recently burned areas at the Fond D’Albaretz also don’t

comprise Dicranopteris l. patches. We therefore suppose that it takes quiet some time until Dicranopteris l.

establishes after a fire disturbance. In addition the establishment of invasive species is heavily depending

on propagule pressure and habitat conditions.

4.8 Fire risk map

The risk depicted in the fire risk map is composed of the likelihood of ignition and the risk to spread a

fire. However, most forest fires are caused unintentionally or intentionally by humans. In this context,

the fire risk map can help to predict, where the fire is likely to spread and where it possibly can be

stopped.

It is striking to see that often on ridges the risk is lower than on the adjacent slopes. Although there are

trails following ridges the influence of the slope on the fire risk seems stronger than the one of the

vicinity to trails. This demonstrates the high influence of topography on the risk of spreading fires. The

topographic roughness of the Fond D’Albaretz is probably a main factor explaining why the Fond

D’Albaretz has an overall high risk. The available fuel is certainly also an important factor determining

the risk. However, there is not much difference in the availability of fuel within the study site. Human

presence is certainly the most important ignition source and combined with steep slopes it can result in

a very high fire risk like in the south-west of the Fond D’Albaretz.

Unfortunately detailed data on forest fires in the area of the Fond D’Albaretz was not available and no

relationships between forest fires and single parameters influencing the risk to spread or induce fire

could be analyzed using the linear regression method. We propose the development of a Praslin-wide

fire risk map for further research. Fire data for Praslin should be available to an extent which allows the

performance of a linear regression study. GIS-data can be obtained from the GIS-Unit at the Policy

Planning and Services Division of the Ministry of Environment on Mahé. The Praslin-wide fire risk map

could be a very useful tool to prevent fires and support fire-fighting.

4.9 Synthesis

In our work hypothesis, we proposed, besides the unique ecological framework of the south-eastern

Praslin, the presence of boulder fields and the lack of severe fire disturbances and human impact as

main reasons for the high ecological value of the Fond D’Albaretz. We found several lines of evidence

supporting this hypothesis.

The boulder field mapping clearly revealed the high presence of interlinked boulder fields within the

study area (Fig. 17). The distribution of boulder fields can be described as a network following valleys

towards the sea. Boulder field classification revealed that boulder fields are a hideaway for threatened

Discussion and conclusions

- 38 -

plant species, which are obviously better adapted to the micro-climatic conditions of boulder fields than

invasive plant species. It could also be proved that endemic palm species prefer growing between big

boulders. Therefore, the Fond D’Albaretz provides a vast habitat for threatened and endemic palm

species.

The combination of the fire risk map, the boulder field map and the locations of few selected rare plant

species all show that these rare species are to a great extent restricted to high fire risk areas enclosed by

boulder fields (Fig. 17). For example, only two specimens of Drypetes r. and two of Northea h. were found,

all located within or enclosed by boulder fields. At first sight this seems not logical because areas with a

high fire risk may have burned in the past and the rare species were therefore locally extinct. However,

due to the isolation by boulder fields, they may have survived in certain locations or rather the fire was

not able to burn the vegetation in those sites because of the boulder fields. Therefore, we propose that

boulder fields have a protective power against fire and that they are able to stop the spread of forest fires

and therefore protect vegetation-patches between big boulder fields.

Fig. 17: Map showing the fire risk, boulder fields and locations of selected rare plant species.

The comparison with the back side of the Fond D’Albaretz suggests that the Fond D’Albaretz has been

less affected by fire disturbances in the past. The presence of the fern Dicranopteris l. is significantly

higher on the northern backside than on the south side of the Fond D’Albaretz. This fern is able to

invade burned and eroded areas (Carlström 1996) and is therefore an evidence for fire disturbances in

the past. Dicranopteris l. is also highly inflammable (Swabey 1970) and poses a high risk to induce or

spread fire. Additionally our results show a higher presence of invasive species on the northern back side

of Fond D’Albaretz, especially for saplings. It is known that introduced species will spread into gaps

caused by fire (Meuwly). We can therefore suggest that the forest on the back side must have been more

fire-disturbed because an undisturbed stable native forest could not have been invaded by alien species

by that extent. A third evidence for a reduced amount of disturbance of the Fond D’Albaretz forest is

personal observation by local people. Reportedly there was no fire event for at least 25 years before the

two fires in 2008 (personal communication Matthieu LaBuschagne 2008).

Discussion and conclusions

- 39 -

4.10 The potential for ecotourism

A main reason for the degradation of forests in general is the motivation to gain economic value out of

areas, e.g. through agricultural use or construction of settlements. An approach to preserve forests and at

the same time gain an economic value is ecotourism, which is defined as “Nature-based tourism that

involves education and interpretation of the natural environment and is managed to be ecologically

sustainable” (Commonwealth Department of Tourism, 1994). A sustainable ecotouristic use is desirable

because it raises people’s awareness of the beauty and uniqueness of the forest and demonstrates that it

must not be destroyed. This experience might motivate tourists to donate for conservation actions,

which are crucial in terms of forest preservation.

These days, the Fond D’Albaretz is already used for ecotourism. Several times a week, tourists have the

opportunity to experience the beauty of the forest on guided walks. However, only a small portion of the

forest (the eastern part of the Jean-Baptiste Nature Trail) is shown and we suggest that there is a huge

potential to expand the adventure for tourists. The potential is founded in the special characteristics of

the Fond D’Albaretz:

• Our results clearly showed that the forest is of outstanding ecological quality throughout.

• Due to its unique character as a relic of an original low-altitude forest, one can feel the

prehistoric time when the Seychelles were still a part of Gondwanaland.

• Sheltering a lot of threatened species, the Fond D’Albaretz is a hotspot in terms of floristics and

biodiversity.

• There is an outstanding scenic potential which can be enjoyed from several easily accessible

view-points.

• The size of the Fond D’Albaretz is optimal for an ecotouristic use: It is large enough that

different plant communities, habitats and scenes can be found and small enough that one can

keep the overview.

• It is an example for human influence on an intermediate forest system.

• The presence of modern threats, e.g. human-caused forest fires or invasive species, clearly shows

the fragility of such a relic forest.

• The fire-succession-process after a disturbance can impressively be shown along the Jean-Baptiste

Nature trail.

• It is a great adventure to explore the nature of the Fond D’Albaretz along the trails.

• The location in the south-east of Praslin is ideal because of its calmness and virginity.

We attest the Fond D’Albaretz an overall importance and suggest implementing the above mentioned

points into a comprehensive ecotourism concept. A first action could be to offer walks on the western

side of the Jean-Baptiste Nature Trail and on the expanded Nature Trail. The comparison of the species

composition along the Jean-Baptiste Nature Trail and the expanded Nature Trail does not show

significant differences. Whereas the eastern part of the Jean-Baptiste Nature Trail is already visited

weekly by tourists, the expanded Nature Trail is nowadays not used much by tourists. Actually, the

expanded Nature Trail is as interesting for tourists as the Jean-Baptiste Nature Trail and has some

specialities to show: In the vicinity of sub-transect 2E the ruins of an old house are visible, giving a good

impression of the impact of humans on the species composition of a forest: In the vicinity of the ruins,

commercial fruit trees like Mangifera i. or Artocarpus a. can be found and also the prominence of

Cinnamomum v. is higher than in other regions.

Due to the remoteness of the expanded Nature Trail, the management of the Hotel Coco de Mer

anticipates the construction of small huts to enable two-day-walks. Based on the present research this

idea indeed bears the potential of not only making tourists aware of how forest ecology in the Seychelles

works, but also to offer people unique contacts with a floristic hotspot in a beautiful, well conserved

surrounding.

Discussion and conclusions

- 40 -

However, there is always a trade-off between the potential damage tourism can do and the benefits of

making people aware of the natural beauty. Construction in remote forest areas and especially a higher

frequency of human presence also pose risks for the vegetation. Thus the concept of guided and

monitored walks should be extended to minimize the impact on the vegetation. We are confident that

the positive aspects of ecotourism outweigh the risk for potential damages.

There are a lot of threatened areas of special conversation value in the Seychelles. We suggest the

concept of ecotourism of the Fond D’Albaretz as a model for nature conservation. A win-win-situation

can be achieved: Valuable areas can be preserved and lead to an increased touristic attractiveness of the

Seychelles. A label could be designed for hotels which preserve nature by means of ecotourism. This

could also build up pressure on hotels which do not follow the idea of ecotourism.

4.11 Recommendations

General site management

The current management actions like removing invasive and planting endemic species should be

continued and if possible expanded. We strongly recommend the documentation of plantings and

cuttings. Especially threatened species should be monitored and even georeferenced with GPS. In order

to organize the management of the Fond D’Albaretz forest properly, we strongly recommend developing

a detailed management plan for the next few years containing objectives, aims and specific actions. It is

also important to define specific tasks and allocate them to competent people. Conservation actions

guided by a management plan are more purposeful than on an ad-hoc basis. It is an ideal mean, to

obtain and improve the ecological value, the scenic potential and the touristic attractiveness of the Fond

D’Albaretz.

With regard to a long term management it would be favourable to have an own plant nursery, which can

deliver desired species and fulfil the special requirement of the Fond D’Albaretz. In case of a fire event,

rehabilitation action would be easier due to the existence of adequate saplings.

To recognize eventual changes in vegetation we recommend a repeating vegetation monitoring. The

baseline was established in this work. Special attention should be given to rehabilitated sites where alien

invasive species were taken out and endemic species were newly planted. It is important to gain more

knowledge about how invasive species can be reduced the best and which species should be planted

afterwards.

Construction work like maintaining and expanding of trails, taking out invasive trees or building the

projected huts should be done very carefully because disturbed sites pose a high potential for invasion.

The canopy should remain as closed as possible and no erosion should be caused.

Management to protect the forest from fire disturbances

To protect the forest from fire events or to prevent the spread of fires we recommend the building of so

called “shaded fuel breaks”. They can efficiently hinder a fire to spread and thus protect the forest.

Instead of logging all plants along a trail, only the understory vegetation should be removed and soil

disturbance should be minimized. By building such shaded fuel breaks it is important to be aware of the

potential of disturbed areas to become invaded. The cleared area on the forest ground represents an

optimal habitat for invaders like Dicranopteris l. or Chrysobalanus i. These two species are able to bridge

adjacent sides separated by shaded fuel breaks. Thus, the canopy should be as closed as possible to

hinder invasive species to come in. The shaded fuel breaks should be maintained regularly to prevent

invasive species to establish and to keep the protective power against the spread of fires.

Discussion and conclusions

- 41 -

Due to the fact that the Jean-Baptiste Nature Trail is maintained and walked weekly, this trail already

acts as a minor fuel break. The fuel breaks protecting the Fond D’Albaretz could be enlarged along the

border of the property and along the expanded Nature Trail.

It is planned to build a fire tower on top of the Jean-Baptiste Nature Trail which collects rain water for

the case of a fire event. This stored water can be used to extinguish fire on-site and is cheaper and faster

than flying sea water in with a helicopter. To fight small fires the building of a fire tower seems

appropriate. However, for extensive fire events the stored water in the fire tower is by far not enough

and other sources and measures are crucial.

Management after a fire disturbance

After a fire event it is very important to protect the soil from erosion and to hinder invasive plant species

to establish. The building of erosion barriers can help to prevent the soil from erosion, especially in

steep areas. Even tough still a lot of nutrients are washed out by rain the hillsides can be stabilized and

the establishment of vegetation supported. Fire-disturbed areas provide a good opportunity for aliens to

establish. Probably the first species coming up are the invasives Adenanthera p. and Clerodendrum s. and

other species which have seeds distributed by birds (personal communication Michael Gill 2008). Also

the fern Dicranopteris l. will most probably establish sooner or later and then prevent other species from

growing. Thus it is very important to support the regeneration-process with maintaining actions like

planting of suitable native species and removing invasive species. Such suitable species are soil stabilizer

like the two sedges Lophoschoenus h. and Costularia f. or species with a high litter production. The

endemic palm Phoenicophorium b. proved to be a helpful species to rehabilitate disturbed areas. It is

robust and due to its high phenotypic plasticity the species can adapt to different habitat types. The leaf

litter produced by Phoenicophorium b. needs a long time to decompose and thus provides a good

protection against erosion.

To gain knowledge about the success of planted species, rehabilitated areas should be monitored. It is

important to distinguish between the planted and the non planted individuals that accurate conclusion

can be drawn. For future post-fire rehabilitation it is of interest which species survive the best and which

of the planted species are able to establish. Especially with regard to the planted endemic species it is of

great interest how they are able to develop in the future.

Fire risk map

Due to the fact that forests on Praslin are repeatedly affected by fire events, we recommend the

development of a Praslin-wide fire risk map. The required spatial data is available besides of locations

and extents of forest fires in the past. Therefore, we recommend creating a database where all fire events,

including date, exact location and extent are recorded. With those data, it would be possible to analyse

which parameters have the biggest influence on the risk to spread or induce fires.

The approach of ecotourism

Ecotourism has the great opportunity to benefit the conservation of the Fond D’Albaretz. To achieve

benefits, we recommend aiming at following targets:

• Generate money for management: It should be ensured that nature tourists contribute

financially to the preservation of the Fond D’Albaretz forest. To raise enough money for a

comprehensive management, the offer should be extended. This can be achieved by offering

guided walks on the western part of the Jean-Baptist Nature Trail and the expanded Nature

Trail or by the possibility for 2-day-walks with accommodation in a hut. There are numerous

other ideas to raise more money for conservation actions: Tourists could buy an endemic

sapling and plant it at an appropriate site, individual walks could be offered for people

interested in specific topics like birds or orchids, “marriage ceremonies in nature” could be

arranged etc.

Discussion and conclusions

- 42 -

• Involve local people and let them profit economically: If enough money can be raised to

establish a management system, jobs will be generated and local people can be hired. If they

profit from the forest, they will less likely have a negative impact on it and acts of arson, e.g. fire

spreading, can be averted.

• Raise people’s awareness of the importance of conservation: This affects not only tourists but

also local decision makers. The Hotel Coco de Mer could serve as a motivation for others to

anticipate an ecotouristic approach.

To avoid negative impacts of a higher human presence in the forest, tourists should be instructed and

guided. Clear rules should be defined and showed on a sign at the entrance of the forest.

4.12 Suitability of methods

Trail transecting

The trail transecting method is very useful and is quite easy to perform. With a relative small

expenditure of time a good overview on the species composition of a forest area can be obtained. Due to

the fact this method is more or less repeatable along the same trails it is possible to compare the gained

data with earlier findings.

Count-plot analysis

Count-plot analysis provides useful information on the stand structure of a forest type. It is

recommended to use this method together with trail transecting. Whereas trail transecting gives an

overview on the species composition of a whole area, the count-plot analysis is only representative for a

small area but provides additionally information about regeneration and tree density.

Photo monitoring

The photo monitoring has to be seen as a complementary method together with trail transecting or

count-plot analysis. It provides a snapshot of the actual state of the vegetation. Performed for several

years the changes in the vegetation can be visualized.

Boulder field classification

This method established by Baader & Hendry (2007) for a palm forest on Mahé was also very useful for

our study site. Due to the fact that it can be performed while doing trail transecting there is no big

additional time needed. The specification between nine different boulder classes also seemed useful

within our study site and it is recommended to retain this classification.

Forest zoning based on nativeness and on red listed endemics

Forest zonings give a good overview on the different parts of a forest and its structural composition. Due

to the fact that each forest has his individual species composition it seems advisable to adapt the

criterions and the zones in each case. Whereas Baader & Hendry (2007) differentiated between several

palm forests, in our study site such a classification would not have been reasonable. However, if the

forest zoning should be comparable with other studies one should rely more or less on the same

criterions.

Zonation based on protection values (PtV)

The protection value gives a good general idea of the protection priority of an area and is very useful to

compare different forest areas. Due to the fact that the protection value is calculated quite broad and

only five levels are distinguished we got for most of the sub-transects the same value. Thus an additional

quantification was done to distinguish the protection value of each sub-transect better. Thereby also

small differences within the sub-transect became visible.

Discussion and conclusions

- 43 -

Dicranopteris linearis survey

The Dicranopteris l. survey, like it was performed for this study, was very useful to get an overview of the

spread of the fern along the sub-transects. However, for doing scientific research about the spread and

establishment of Dicranopteris l. a more precise method should be developed.

Boulder field mapping

Owing to the combination of satellite imagery and field trips a bright overview on the boulder fields

within the study site could be gained. Especially in the vicinity of the trails a lot of information about

the location, extent and structure of boulder fields were gathered. However, it was not possible to cross

the forest everywhere and to ensure that all boulder fields are mapped.

Qualitative monitoring of post-fire areas

This method was designed to deal with the lost plots at Fond Ferdinand. No quantitative resurvey was

possible and time was scarce. The qualitative monitoring method used enabled us to gain a lot of useful

information. However, quantitative methods likes trail transecting and count-plot analysis are

recommended. Due to the fact that these two methods are more precise, it is possible to repeat the

monitoring in future research projects the same way and changes in the vegetation can be observed

better.

Fire risk map

The GIS-analysis effectively integrates different risk-parameters to a single map which visualizes the fire

risk of the whole area. High fire risk areas can be identified and possible spreads of fire estimated.

However, due to a lack of fire data, no linear regression could be performed to investigate the

importance of the different risk factors.

- 44 -

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- 46 -

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix -

A Plant List Fond D’Albaretz

B Monitoring Protocols

C Sampling Plots: Data

D Trail Transects: Data

E Fire Risk Map: Geoprocessing Models

F List of planted species in the burned area

- Digital Appendix - The digital appendix can be found on the CD.

G Sampling Plots: General descriptions, Data,

Photo-Monitoring and Sketches

H Trail Transects: Photo-Monitoring, Data

I Literature

K Report

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix A -

Plant List Fond D’Albaretz

Plant List Fond D'Albaretz (Based on Trail Transecting and Count Plot Analysis)

Species Creol name StatusRed list status

(Huber&Ismail, 2006)

Adenanthera pavonina Agati Invasive

Allophylus pervillei Bois cafoul Indigenous

Allophylus sechellensis Bois cafoul trois feuilles Endemic VU

Alstonia macrophylla Bois jaune Invasive

Anacardium occidentale Cajou Invasive

Aphloia theiformis var. seychellensis Bois merles Endemic VU

Artocarpus altilis Bread fruit Alien

Averrhoa bilimbi Bilimbi Alien

Bambusa vulgaris Bambou jaune Alien

Calophyllum inophyllum Takamaka Indigenous

Canthium bibracteatum Bois dur rouge Indigenous

Casuarina equisetifolia Cèdre Invasive

Chrysobalanus icaco Prune de France Invasive

Cinnamomum verum Cannelle Invasive

Clerodendrum speciosissimum Modestie rouge Invasive

Craterispermum microdon Bois doux Endemic EN

Deckenia nobilis Palmiste Endemic NT

Dillenia ferruginea Bois rouge Endemic VU

Diospyros sechellarum Bois sagaye Endemic NT

Dracaena reflexa Bois chandelle blanc Indigenous

Drypetes riseleyi Bois maré petite feuille Endemic CR

Erythroxylum sechellarum Café marron petite feuille Endemic LC

Euphorbia pyrifolia Bois du lait Indigenous

Ficus lutea Afouche grande feuille Indigenous

Gastonia crassa Bois banane Endemic VU

Haematoxylum campechianum Campèche Alien

Intsia bijuga Gaïac Indigenous

Leucaena leucocephala Cassie Invasive

Lodoicea maldivica Coco de Mer Endemic VU

Ludia mauritiana var. sechellensis Prunier marron Endemic VU

Mangifera indica Manguier Alien

Memecylon elaeagni Bois calou Endemic LC

Nephrosperma vanhoutteanum Latanier millepatte Endemic VU

Northea hornei Capucin Endemic VU

Ochna ciliata Bois démon Invasive

Pandanus multispicatus Vacoa de montagne Endemic NT

Pandanus sechellarum Vacoa marron Endemic NT

Paragenipa wrightii Café marron grande feuille Endemic NT

Phoenicophorium borsigianum Latanier feuille Endemic LC

Pouteria obovata Bois mon père Indigenous

Premna serratifolia Bois siro Indigenous

Psidium cattleianum Gouyave de Chine Invasive

Psychotria pervillei Bois couleuvre Endemic VU

Syzygium wrightii Bois pomme Endemic VU

Tabebuia palida Calice du pape Invasive

Terminalia catappa Badamier Indigenous

Verschaffeltia splendida Latanier latte Endemic VU

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix B -

Monitoring Protocols

Farrèr & Hertach (2008), Fond D'Albaretz Project

Plot-Nr.: Date: Slope:

Marker tree (Coordinates and description):

Soil Granulation Degradation

(from central point of plot)

□ Clay (< 2mm) □ natural conditions

□ Silt (2-50mm) □ 0% □ close to natural conditions

□ Sand (50-2000mm) □ 1-25% □ altered, visible human impact:

□ Gravel □ 26-50% …

□ Stones □ 51-75% □ degraded

□ Blocks/Boulders □ 76-100% □ heavily degraded

Dicranopteris l.

North

East

South

West

Litter

Corner

North

East

South

West

General view

Herb-layer

Corner Litter (Species) Plant species Surrounding area other observations

North

East

South

West

r 1-2 individual

General Description

Canopy Openness

BB-Category Cover

BB-Category + Covering < 1% of the area

1 Covering 1-5% of the area

4 Covering 50-75% of the area

5 Covering > 75% of the area

2 Covering 5-25% of the area

3 Covering 25-50% of the area

BB-Category Species (dominating species is underlined)

Plant species

Surrounding area

Dead trees

other observations

Photo Monitoring

Farrèr & Hertach (2008), Fond D'Albaretz Project

Date: GPS-Coordinates of marker tree:

[m]Adult (T: h >2m, dhb>3cm;

P: leaves > 100cm, true stem)

Sapling (T: 0.5-2m, dhb <3cm;

P: leaves>100cm, no stem)

M. prom. Seedling (T: <0.5m,

<3cm; P: <100cm, no stem)Comments / Geographic features

0 PhM, Boulder-F., GPS-Point

2

4

6

8

10 Boulder-F.

12

14

16

18

20 Boulder-F.

22

24

26

28

30 Boulder-F.

32

34

36

38

40 Boulder-F.

42

44

46

48

50 Boulder-F.

52

54

56

58

60 Boulder-F.

62

64

66

68

70 Boulder-F.

72

74

76

78

80 Boulder-F.

82

84

86

88

90 Boulder-F.

92

94

96

TRAIL TRANSECTING

Subtransect-Nr.:

Nr.Adult (T: h >2m, dhb>3cm;

P: leaves > 100cm, true stem)

Sapling (T: 0.5-2m, dhb <3cm;

P: leaves>100cm, no stem)

M. prom. Seedling (T: <0.5m,

<3cm; P: <100cm, no stem)Comments / Geographic features

98

100 Boulder-F., GPS-Point

102

104

106

108

110 Boulder-F.

112

114

116

118

120 Boulder-F.

122

124

126

128

130 Boulder-F.

132

134

136

138

140 Boulder-F.

142

144

146

148

150 Boulder-F.

152

154

156

158

160 Boulder-F.

162

164

166

168

170 Boulder-F.

172

174

176

178

180 Boulder-F.

182

184

186

188

190 Boulder-F.

192

194

196

198

200 Boulder-F.

Farrèr & Hertach (2008), Fond D'Albaretz Project

Plot-Nr.: Date:

Adults, dbh (cm) North East South West Tot

Sapling, height (cm) Tot

Seedling, # Tot

West

Count Plot Analysis

North East South

North East South West

SUBTRANSECT: SIDE: □ LEFT, □ RIGHT

length (m) height (m) No length (m) height (m) No

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

1 Distance form the start of the trail subtransect Class Description Cover2 % boulder-coverage of the ground within 10m-belt 1 03 If the sizes of several boulders within one 10m-belt vary significantly, 1a 0

a second estimation for this boulder sizes can be noted here 2 ≥ 50%4 Total number of individual boulders counted within the 10m-belt 2a < 50%

3 ≥ 50%

3a < 50%

4 ≥ 50%

4a < 50%

Farrèr & Hertach (2008), Fond D'Albaretz Project 5 -Bluffs of rock H > 4m, L > 8m

Boulder field with huge boulders 2m < H ≤ 4m, 2m < L ≤ 8m

Area wiht a few huge boulders 2m < H ≤ 4m, 2m < L ≤ 8m

Boulder field with mixed boulder sizes H,L: > 0.5m and ≤ 2m

Area with a few different sized boulders H,L: > 0.5m and ≤ 2m

-

Area without boulders between bluffs of rocks No boulders

Area with a few small boulders H: ≤ 0.5m, L: ≤ 0.5m

Boulder field with small boulders H: ≤ 0.5m, L: ≤ 0.5m

Definition

Area without boulders

Remarks Adult (T: h >2m, dhb>3cm;

P: leaves > 100cm, true stem)

Sapling (T: 0.5-2m, dhb <3cm;

P: leaves>100cm, no stem)Remarks

BOULDER FIELD CLASSIFICATION

Boulders (within 10m perpendicular to trail, every 10m) Plants (most p. species within 10m perpendicular to trail)

[m] 1

% 2 Size of Boulder Size of Boulder 2

3

Total 4 Classes

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix C -

Sampling Plots: Data

Sampling Plot A

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 29.7 5.1 20.2 14.4

Allophylus p. 0.0 0.0 0.0 13.4

Anacardium o. 22.8 11.4 40.4 0.0

Calophyllum i. 0.0 0.0 0.0 5.1

Chrysobalanus i. 0.0 0.0 0.0 4.2

Cinnamomum v. 0.0 0.0 0.0 44.1

Deckenia n. 7.6 1.0 0.0 0.0

Dracaena r. 0.0 0.0 20.2 8.6

Dillenia f. 7.6 6.3 0.0 0.0

Ludia m. 0.0 0.0 0.0 4.2

Nephrosperma v. 0.0 0.0 0.0 8.0

Paragenipa w. 74.5 40.9 29.3 5.4

Phoenicophorium b. 22.8 14.5 40.4 44.4

Pouteria o. 35.0 20.8 49.5 48.2

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot B

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Allophylus p. 0.0 0.0 0.0 5.3

Canthium b. 0.0 0.0 0.0 5.3

Cinnamomum v. 0.0 0.0 0.0 20.0

Deckenia n. 31.0 4.2 16.3 6.9

Dracaena r. 0.0 0.0 16.3 5.3

Ludia m. 0.0 0.0 0.0 5.3

Nephrosperma v. 10.3 2.2 0.0 21.6

Paragenipa w. 88.7 80.9 48.8 18.4

Phoenicophorium b. 54.5 11.9 73.8 59.5

Pouteria o. 15.6 0.7 45.0 52.3

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot C

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 9.7 1.0 0.0 7.9

Allophylus p. 0.0 0.0 0.0 12.0

Allophylus s. 0.0 0.0 0.0 5.1

Canthium b. 22.4 2.3 0.0 8.3

Chrysobalanus i. 0.0 0.0 28.6 0.0

Cinnamomum v. 0.0 0.0 0.0 20.4

Deckenia n. 0.0 0.0 57.1 6.8

Diospyros s. 9.7 0.3 0.0 2.6

Dracaena r. 0.0 0.0 28.6 5.1

Ludia m. 0.0 0.0 0.0 7.7

Memecylon e. 12.7 0.5 0.0 43.5

Nephrosperma v. 9.7 0.3 28.6 13.5

Paragenipa w. 60.0 58.4 28.6 13.2

Phoenicophorium b. 66.1 31.0 0.0 40.5

Pouteria o. 0.0 0.0 28.6 13.3

Syzygium w. 9.7 6.3 0.0 0.0

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot D

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Allophylus p. 0.0 0.0 0.0 11.2

Allophylus s. 0.0 0.0 0.0 6.9

Canthium b. 14.5 0.5 0.0 3.4

Chrysobalanus i. 0.0 0.0 40.0 7.0

Cinnamomum v. 14.5 21.7 44.0 107.8

Deckenia n. 17.2 10.8 10.7 0.0

Diospyros s. 7.2 9.5 0.0 3.4

Dracaena r. 0.0 0.0 0.0 6.7

Erythroxylum s. 7.2 0.3 0.0 0.0

Memecylon e. 17.2 1.6 0.0 6.9

Nephrosperma v. 34.4 24.3 0.0 14.6

Paragenipa w. 27.1 2.9 10.7 7.3

Phoenicophorium b. 53.3 28.0 54.7 10.8

Pouteria o. 7.2 0.3 40.0 14.1

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot E

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 36.9 17.5 0.0 78.8

Chrysobalanus i. 0.0 0.0 0.0 7.3

Cinnamomum v. 53.7 40.0 121.4 46.5

Dracaena r. 0.0 0.0 0.0 7.3

Ludia m. 0.0 0.0 0.0 10.9

Memecylon e. 0.0 0.0 0.0 3.6

Nephrosperma v. 37.6 29.1 0.0 15.6

Paragenipa w. 0.0 0.0 0.0 3.6

Phoenicophorium b. 51.2 13.3 39.3 11.0

Pouteria o. 20.7 0.2 39.3 15.3

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot F

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 16.4 1.9 22.5 6.2

Allophylus p. 0.0 0.0 0.0 3.1

Allophylus s. 0.0 0.0 0.0 3.3

Calophyllum i. 0.0 0.0 0.0 3.1

Canthium b. 0.0 0.0 0.0 12.2

Cinnamomum v. 0.0 0.0 0.0 19.5

Dillenia f. 18.4 43.5 0.0 0.0

Dracaena r. 8.2 1.3 0.0 3.1

Erythroxylum s. 8.2 0.6 0.0 3.1

Ludia m. 0.0 0.0 0.0 9.7

Memecylon e. 0.0 0.0 0.0 3.1

Nephrosperma v. 0.0 0.0 0.0 16.2

Ochna c. 0.0 0.0 0.0 3.1

Paragenipa w. 70.1 43.7 90.0 17.2

Phoenicophorium b. 52.5 6.4 87.5 65.8

Pouteria o. 26.2 2.7 0.0 31.4

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot G

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 30.7 24.8 0.0 41.5

Allophylus p. 0.0 0.0 0.0 9.2

Allophylus s. 0.0 0.0 0.0 4.7

Canthium b. 13.3 0.7 0.0 0.0

Cinnamomum v. 26.5 0.9 50.0 85.5

Dracaena r. 0.0 0.0 0.0 13.6

Ludia m. 0.0 0.0 0.0 16.0

Nephrosperma v. 0.0 0.0 0.0 4.5

Paragenipa w. 13.3 0.7 0.0 0.0

Phoenicophorium b. 103.0 71.2 150.0 11.1

Pouteria o. 0.0 0.0 0.0 13.9

Verschaffeltia s. 13.3 1.7 0.0 0.0

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot H

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 0.0 0.0 0.0 5.5

Alstonia m. 0.0 0.0 17.7 0.0

Canthium b. 24.0 0.3 76.2 36.3

Cinnamomum v. 0.0 0.0 0.0 5.5

Dracaena r. 0.0 0.0 0.0 5.5

Erythroxylum s. 0.0 0.0 35.4 5.5

Memecylon e. 0.0 0.0 17.7 0.0

Nephrosperma v. 0.0 0.0 0.0 10.9

Paragenipa w. 137.8 92.8 0.0 19.8

Phoenicophorium b. 20.7 0.5 17.7 59.7

Pouteria o. 17.5 6.4 17.7 51.5

Tabebuia p. 0.0 0.0 17.7 0.0

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Sampling Plot I

Saplings Seedlings

[PV1] [dbh-dom.

2] [PV

1] [PV

1]

Adenanthera p. 17.8 0.3 0.0 23.0

Allophylus s. 0.0 0.0 0.0 8.0

Calophyllum i. 0.0 0.0 0.0 7.8

Chrysobalanus i. 0.0 0.0 0.0 11.9

Cinnamomum v. 17.8 10.9 0.0 97.1

Dracaena r. 0.0 0.0 0.0 3.9

Nephrosperma v. 0.0 0.0 0.0 8.0

Paragenipa w. 0.0 0.0 0.0 3.9

Phoenicophorium b. 123.7 87.8 200.0 19.0

Pouteria o. 40.8 0.9 0.0 17.4

1 PV: Prominence Value

2 dbh-dom.: Relative dominance in % based on cumulated dbhs

Adult Trees

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix D -

Trail Transects: Data

Trail Transecting Data Adult: Fond D'Albaretz (Jean Baptiste Nature Trail & expanded Nature Trail)

Ad

en

an

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ph

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Allo

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Als

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Art

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Ave

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b.

Ba

mb

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Ca

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b.

Ca

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Ca

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Ch

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lan

us

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Cin

na

mo

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Cle

rod

en

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Cra

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De

cke

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Dille

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f.

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Dra

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na

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Dry

pe

tes

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Eu

ph

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Fic

us

l.

Ha

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ato

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m c

.

Ints

ia b

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Lod

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m.

Lud

ia m

.

1A 1 3 3 4 4 3 2 2 1 10 3 1

1B 1 1 16 2 5 6 3 4 5 8

1C 2 2 4 3 1 2 4 6 4 4 2 2

1D 1 1 1 2 1 12 1 5 2

1E 4 2 3 6 1 1 12 3 1 3 2 2 1

1F 2 3 9 1 9 6 2 1 2

1G 2 1 1 2 1 2 2 18 1 4 5 4

1H 1 4 3 2 1 6 5 1 2 3

2A 2 2 5 1 10 5 5 4 1 2 2 1

2B 4 1 1 5 4 2 8 1 1 1

2C 16 3 2 6 1 3 1

2D 6 1 1 5 4 3

2E 5 1 1 4 1 1 36 1 2

2F 7 1 3 3 2 1 1 4 1 10 2 3 2

2G 3 3 2 2 1 5 3 9 7 1 1

2H 1 3 6 12 1 4 2 7 2 1

Sum 52 10 3 2 20 3 1 3 64 20 14 26 106 1 2 35 99 11 19 4 48 2 5 13 10 4 8

Frequency 13 5 1 2 8 1 1 1 15 9 10 10 13 1 1 14 14 3 8 1 13 1 3 4 6 2 5

%-Frequency 4.96 1.91 0.38 0.76 3.05 0.38 0.38 0.38 5.73 3.44 3.82 3.82 4.96 0.38 0.38 5.34 5.34 1.15 3.05 0.38 4.96 0.38 1.15 1.53 2.29 0.76 1.91

1A 1 0 2 0 2 0 0 0 2 2 2 2 2 0 0 1 4 0 0 0 2 0 0 1 0 0 0

1B 0 0 0 1 1 0 0 0 4 2 0 3 3 0 0 2 2 0 0 0 3 0 0 3 0 0 0

1C 2 2 0 0 2 0 0 0 2 1 2 0 2 0 0 3 2 0 0 0 2 0 2 2 0 0 0

1D 1 0 0 0 0 0 0 0 1 0 1 2 0 0 0 1 4 0 1 0 3 0 0 0 0 2 0

1E 0 2 0 0 2 0 0 2 3 0 1 1 4 0 0 2 1 0 2 0 2 0 0 2 1 0 0

1F 2 0 0 0 2 0 0 0 4 1 0 0 0 0 0 0 4 0 3 0 2 0 1 0 2 0 0

1G 2 1 0 1 0 0 0 0 2 1 0 0 2 0 0 2 5 0 1 2 3 0 0 0 0 0 2

1H 1 0 0 0 0 0 0 0 2 0 0 2 0 0 2 1 3 3 1 0 2 0 0 0 2 0 0

2A 2 2 0 0 0 0 0 0 3 0 1 0 4 0 0 3 0 3 2 0 1 2 0 0 2 0 1

2B 2 0 0 0 0 0 0 0 1 0 1 3 2 0 0 2 3 1 1 0 0 0 0 0 0 0 1

2C 4 0 0 0 0 0 0 0 0 2 2 0 3 0 0 1 2 0 0 0 0 0 0 0 0 0 1

2D 3 0 0 0 0 0 0 0 1 0 0 1 3 0 0 2 2 0 0 0 0 0 0 0 0 0 0

2E 3 0 0 0 0 0 1 0 1 2 1 1 6 0 0 1 0 0 0 0 2 0 0 0 0 0 0

2F 3 0 0 0 1 2 0 0 2 2 1 1 2 0 0 1 4 0 2 0 2 0 0 0 0 2 0

2G 2 0 0 0 2 0 0 0 2 2 1 3 2 0 0 0 4 0 0 0 3 0 0 0 1 0 1

2H 0 1 0 0 2 0 0 0 3 0 0 0 4 1 0 2 2 0 0 0 3 0 2 0 1 0 0

Abundance 28 8 2 2 14 2 1 2 33 15 13 19 39 1 2 24 42 7 13 2 30 2 5 8 9 4 6

%-Abundance 4.38 1.25 0.31 0.31 2.19 0.31 0.16 0.31 5.16 2.35 2.03 2.97 6.10 0.16 0.31 3.76 6.57 1.10 2.03 0.31 4.69 0.31 0.78 1.25 1.41 0.63 0.94

Prominence Value 9.34 3.16 0.69 1.08 5.24 0.69 0.54 0.69 10.89 5.78 5.85 6.79 11.07 0.54 0.69 9.10 11.92 2.24 5.09 0.69 9.66 0.69 1.93 2.78 3.70 1.39 2.85

indigenous alienendemic invasive

Me

me

cylo

n e

.

Ne

ph

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erm

a v

.

No

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ea

h.

Och

na

c.

Pa

nd

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m.

Pa

nd

an

us

s.

Pa

rag

en

ipa

w.

Ph

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nic

op

ho

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m b

.

Po

ute

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Pre

mn

a s

.

Psi

diu

m c

.

Sy

zyg

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w.

Ta

be

bu

ia p

.

Te

rmin

alia

c.

Ve

rsch

aff

elt

ia s

.

To

tal

2 36 7 14 4 100

2 29 8 9 1 100

36 18 10 100

5 1 33 23 10 98

1 3 26 14 15 100

2 2 24 25 10 1 1 100

1 13 37 5 1 100

7 9 29 15 9 3 100

11 10 2 11 22 3 1 100

8 9 1 1 19 27 4 3 100

21 2 7 31 1 1 5 100

2 3 8 8 42 8 9 100

5 11 6 21 5 100

1 4 4 16 28 3 2 2 100

1 2 7 24 13 15 1 100

1 4 23 17 6 2 8 100

32 78 2 2 4 35 340 348 127 2 1 8 16 3 15 1598

8 13 1 1 3 7 16 16 16 1 1 4 5 2 3 262

3.05 4.96 0.38 0.38 1.15 2.67 6.11 6.11 6.11 0.38 0.38 1.53 1.91 0.76 1.15 100

0 0 0 2 0 0 6 3 4 0 0 0 2 0 0 40

0 2 0 0 0 0 5 3 4 0 0 1 0 0 0 39

0 0 0 0 0 0 6 5 4 0 0 0 0 0 0 39

0 3 0 0 1 0 6 5 4 0 0 0 0 0 0 35

1 2 0 0 0 0 5 4 4 0 0 0 0 0 0 41

0 0 2 0 0 2 5 5 4 0 0 0 1 0 1 41

0 1 0 0 0 0 4 6 3 0 0 1 0 0 0 39

3 4 0 0 0 0 5 4 4 0 0 2 0 0 0 41

4 4 0 0 2 0 4 5 2 0 1 0 0 0 0 48

3 4 0 0 1 1 5 5 2 0 0 2 0 0 0 40

0 5 0 0 0 2 3 5 1 0 0 0 0 1 3 35

2 2 0 0 0 3 3 6 3 0 0 0 0 0 4 35

0 3 0 0 0 4 3 5 3 0 0 0 0 0 0 36

1 2 0 0 0 2 4 5 2 0 0 0 2 2 0 45

1 2 0 0 0 3 5 4 4 0 0 0 1 0 0 43

1 2 0 0 0 0 5 5 3 2 0 0 3 0 0 42

16 36 2 2 4 17 74 75 51 2 1 6 9 3 8 639

2.50 5.63 0.31 0.31 0.63 2.66 11.58 11.74 7.98 0.31 0.16 0.94 1.41 0.47 1.25 100

5.56 10.60 0.69 0.69 1.77 5.33 17.69 17.84 14.09 0.69 0.54 2.47 3.32 1.23 2.40 200

Trail Transecting Data Sapling: Fond D'Albaretz (Jean Baptiste Nature Trail & expanded Nature Trail)

Ad

en

an

the

ra p

.

Allo

ph

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s p

.

An

aca

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Ap

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Ca

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b.

Ca

lop

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m i.

Ca

sua

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a e

.

Ch

ryso

ba

lan

us

i.

Cin

na

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mu

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.

De

cke

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n.

Dille

nia

f.

Dio

spy

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s.

Dra

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na

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Ery

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Fic

us

l.

Ga

sto

nia

c.

Ha

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ato

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m c

.

Ints

ia b

.

Leu

cae

na

l.

Lod

oic

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m.

Lud

ia m

.

Ma

ng

ife

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Me

me

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.

Ne

ph

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a v

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Och

na

c.

Pa

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us

m.

Pa

nd

an

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s.

1A 2 4 6 1 9 1 3 1 1 3 3

1B 9 1 21 1 6 1 1 1 2 6

1C 1 4 1 2 2 11 2 2 1 2 1

1D 1 2 4 12 1 2 3 13

1E 4 1 12 2 4 5 1 2 1 8

1F 2 1 3 7 2 8 1 1 1

1G 1 1 3 1 3 2 10 1 10 1 4

1H 2 3 1 10 2 1 2 1 2 5 14

2A 13 2 1 5 8 1 4 25

2B 2 19 5 1 1 2 18

2C 1 3 15 1 16

2D 5 2 1 1 2 12 2

2E 1 3 13 1 1 10

2F 1 2 2 7 4 1 4 5

2G 9 3 3 1 1 7 2

2H 1 4 3 5 5 5 1 1 6

Sum 3 23 5 1 49 15 2 103 66 56 11 1 50 3 1 1 6 1 1 3 2 1 14 150 4 2 2

Frequency 3 6 4 1 12 7 2 15 13 10 9 1 14 3 1 1 4 1 1 1 2 1 6 16 2 1 1

%-Frequency 1.57 3.14 2.09 0.52 6.28 3.66 1.05 7.85 6.81 5.24 4.71 0.52 7.33 1.57 0.52 0.52 2.09 0.52 0.52 0.52 1.05 0.52 3.14 8.38 1.05 0.52 0.52

1A 0 0 2 0 2 3 1 4 0 0 1 0 2 0 0 0 1 0 1 0 0 0 0 2 2 0 0

1B 0 0 0 0 4 0 1 5 1 3 1 0 1 1 0 0 2 0 0 0 0 0 0 3 0 0 0

1C 0 0 1 0 2 1 0 2 2 4 2 0 2 0 0 0 1 0 0 0 0 0 0 2 1 0 0

1D 0 0 1 0 2 0 0 2 0 4 1 0 2 0 0 0 0 0 0 2 0 0 0 4 0 0 0

1E 0 2 1 0 4 2 0 2 3 0 0 0 1 0 0 0 2 0 0 0 0 0 1 3 0 0 0

1F 0 0 0 0 2 1 0 2 3 2 0 0 3 0 0 0 0 1 0 0 1 0 0 1 0 0 0

1G 0 1 0 1 2 1 0 2 2 4 1 0 4 0 0 0 0 0 0 0 0 0 1 2 0 0 0

1H 0 2 0 0 2 1 0 4 2 1 2 1 2 0 0 0 0 0 0 0 0 0 3 4 0 0 0

2A 0 4 0 0 2 0 0 1 0 3 0 0 3 0 0 0 0 0 0 0 1 0 2 5 0 0 0

2B 0 0 0 0 2 0 0 5 3 0 0 0 1 0 0 1 0 0 0 0 0 0 2 5 0 0 0

2C 1 0 0 0 0 0 0 2 4 0 0 0 0 0 0 0 0 0 0 0 0 0 1 4 0 0 0

2D 0 0 0 0 0 0 0 3 2 1 1 0 2 0 0 0 0 0 0 0 0 0 0 4 0 2 0

2E 1 0 0 0 0 0 0 2 4 0 0 0 1 0 0 0 0 0 0 0 0 1 0 4 0 0 0

2F 1 2 0 0 2 0 0 3 2 0 1 0 2 0 0 0 0 0 0 0 0 0 0 3 0 0 0

2G 0 0 0 0 0 0 0 4 2 2 1 0 0 1 0 0 0 0 0 0 0 0 0 3 0 0 2

2H 0 1 0 0 2 2 0 0 3 3 0 0 3 1 1 0 0 0 0 0 0 0 0 3 0 0 0

Abundance 3 12 5 1 28 11 2 43 33 27 11 1 29 3 1 1 6 1 1 2 2 1 10 52 3 2 2

%-Abundance 0.61 2.44 1.02 0.20 5.70 2.24 0.41 8.76 6.72 5.50 2.24 0.20 5.91 0.61 0.20 0.20 1.22 0.20 0.20 0.41 0.41 0.20 2.04 10.59 0.61 0.41 0.41

Prominence Value 2.18 5.59 3.11 0.73 11.99 5.91 1.45 16.61 13.53 10.73 6.95 0.73 13.24 2.18 0.73 0.73 3.32 0.73 0.73 0.93 1.45 0.73 5.18 18.97 1.66 0.93 0.93

endemic invasive indigenous alien

Pa

rag

en

ipa

w.

Ph

oe

nic

op

ho

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m b

.

Po

ute

ria

o.

Psy

cho

tria

p.

Ta

be

bu

ia p

.

Ve

rsch

aff

elt

ia s

.

To

tal

27 16 20 97

17 16 18 100

8 52 9 1 99

4 52 4 98

12 27 21 100

4 60 7 3 100

3 52 7 99

4 41 11 99

3 35 3 100

3 42 3 1 97

2 60 1 1 100

5 69 99

2 67 2 100

11 58 5 100

9 57 5 2 99

11 44 11 2 99

125 748 127 1 8 1 1586

16 16 15 1 4 1 191

8.38 8.38 7.85 0.52 2.09 0.52 100

5 4 5 0 0 0 35

5 4 5 0 0 0 36

3 6 4 0 1 0 34

2 6 2 0 0 0 28

4 5 5 0 0 0 35

2 6 3 0 2 0 29

2 6 3 0 0 0 32

2 6 4 0 0 0 36

2 6 2 0 0 0 31

2 6 2 1 0 0 30

2 6 1 0 0 1 22

3 7 0 0 0 0 25

2 7 2 0 0 0 24

4 6 3 0 0 0 29

4 6 3 0 2 0 30

4 6 4 0 2 0 35

48 93 48 1 7 1 491

9.78 18.94 9.78 0.20 1.43 0.20 100

18.15 27.32 17.63 0.73 3.52 0.73 200

Trail Transecting Data Seedling: Fond D'Albaretz (Jean Baptiste Nature Trail & expanded Nature Trail)

Ad

en

an

the

ra p

.

Allo

ph

ylu

s p

.

An

aca

rdiu

m o

.

Ap

hlo

ia s

.

Ca

nth

ium

b.

Ca

lop

hy

llu

m i.

Ca

sua

rin

a e

.

Ch

ryso

ba

lan

us

i.

Cin

na

mo

mu

m v

.

De

cke

nia

n.

Dio

spy

ros

s.

Dra

cae

na

r.

Ery

thro

xylu

m s

.

Eu

ph

orb

ia p

.

Ha

em

ato

xylu

m c

.

Leu

cae

na

l.

Lod

oic

ea

m.

Lud

ia m

.

Me

me

cylo

n e

.

Ne

ph

rosp

erm

a v

.

Och

na

c.

Pa

rag

en

ipa

w.

Ph

oe

nic

op

ho

riu

m b

.

Po

ute

ria

o.

Psy

cho

tria

p.

Ta

be

bu

ia p

.

To

tal

1A 16 7 1 5 5 3 1 10 21 22 3 94

1B 20 20 12 6 1 4 2 2 3 9 18 97

1C 13 13 17 3 5 21 23 95

1D 7 4 3 8 1 14 4 22 15 78

1E 3 1 14 3 25 5 3 1 12 17 84

1F 4 9 1 13 2 4 6 1 31 22 93

1G 7 2 2 7 18 5 1 8 6 5 14 13 88

1H 1 2 1 2 4 10 3 1 8 23 1 22 15 93

2A 11 6 4 1 21 1 4 1 4 2 13 4 14 1 1 88

2B 9 1 8 51 6 2 10 3 90

2C 36 1 2 53 1 4 97

2D 34 1 9 26 1 5 2 6 1 85

2E 8 1 74 5 3 1 92

2F 21 16 27 2 1 4 4 1 4 80

2G 3 1 2 1 8 19 1 1 2 1 1 6 1 47

2H 1 3 1 39 3 8 11 7 2 75

Sum 153 13 2 3 89 4 1 80 409 42 1 13 1 1 9 3 0 16 13 97 2 51 198 168 1 6 1376

Frequency 12 6 1 2 13 4 1 11 16 7 1 7 1 1 2 1 0 3 5 15 1 14 15 15 1 3 158

%-Frequency 7.59 3.80 0.63 1.27 8.23 2.53 0.63 6.96 10.13 4.43 0.63 4.43 0.63 0.63 1.27 0.63 0.00 1.90 3.16 9.49 0.63 8.86 9.49 9.49 0.63 1.90 100

1A 4 0 0 0 3 0 1 3 3 0 0 0 0 0 0 2 0 0 0 1 0 4 5 5 0 2 33

1B 0 0 0 0 5 0 0 5 4 3 0 0 1 0 2 0 0 0 0 2 2 2 4 5 0 0 35

1C 0 0 0 0 4 0 0 0 4 5 0 0 0 0 0 0 0 0 0 2 0 3 5 5 0 0 28

1D 0 0 0 0 3 0 0 2 2 3 0 1 0 0 0 0 0 0 0 4 0 2 5 4 0 0 26

1E 2 1 0 0 4 0 0 2 5 0 0 0 0 0 3 0 0 0 0 2 0 1 4 5 0 0 29

1F 2 0 0 0 4 0 0 1 4 2 0 0 0 0 0 0 0 2 0 3 0 1 5 5 0 0 29

1G 3 2 0 2 3 0 0 0 5 3 0 1 0 0 0 0 0 3 0 3 0 3 4 4 0 0 36

1H 1 2 0 1 2 0 0 2 4 2 0 1 0 0 0 0 0 0 3 5 0 1 5 4 0 0 33

2A 4 3 0 0 2 1 0 0 5 0 1 2 0 1 0 0 0 2 2 4 0 2 4 1 1 0 35

2B 4 0 0 0 1 0 0 3 6 0 0 0 0 0 0 0 0 0 0 3 0 2 4 2 0 0 25

2C 6 0 0 0 1 0 0 2 6 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 18

2D 6 0 0 0 1 0 0 4 5 0 0 0 0 0 0 0 0 0 1 3 0 2 3 1 0 0 26

2E 3 0 0 0 0 1 0 0 7 0 0 0 0 0 0 0 0 0 0 3 0 0 2 1 0 0 17

2F 5 0 0 0 0 0 0 4 5 0 0 2 0 0 0 0 0 0 1 2 0 2 1 2 0 0 24

2G 2 1 2 0 0 1 0 3 5 0 0 1 0 0 0 0 0 0 1 2 0 1 1 3 0 1 24

2H 0 1 0 0 2 1 0 0 6 0 0 2 0 0 0 0 0 0 0 0 0 3 4 3 0 2 24

Abundance 42 10 2 3 35 4 1 31 76 19 1 10 1 1 5 2 0 7 8 41 2 29 56 50 1 5 442

%-Abundance 9.50 2.26 0.45 0.68 7.92 0.90 0.23 7.01 17.19 4.30 0.23 2.26 0.23 0.23 1.13 0.45 0.00 1.58 1.81 9.28 0.45 6.56 12.67 11.31 0.23 1.13 100

Prominence Value 17.10 6.06 1.09 1.94 16.15 3.44 0.86 13.98 27.32 8.73 0.86 6.69 0.86 0.86 2.40 1.09 0.00 3.48 4.97 18.77 1.09 15.42 22.16 20.81 0.86 3.03 200

endemic invasive indigenous alien

Trail Transecting Data: Glacis Noir Trail

ADULT

An

aca

rdiu

m o

.

Ap

hlo

ia s

.

Ca

nth

ium

b.

Ca

sua

rin

a e

.

Ch

ryso

ba

lan

us

i.

Cin

na

mo

mu

m v

.

De

cke

nia

n.

Dille

nia

f.

Ery

thro

xylu

m s

.

Lud

ia m

.

Me

me

cylo

n e

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Ne

ph

rosp

erm

a v

.

Pa

rag

en

ipa

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Ph

oe

nic

op

ho

riu

m b

.

Po

ute

ria

o.

Sy

zyg

ium

j.

Sy

zyg

ium

w.

To

tal

3A 1 5 2 19 2 7 8 5 2 17 19 6 7 100

3B 2 7 2 18 15 3 3 1 4 13 22 6 1 3 100

Sum 1 2 12 4 37 17 10 11 5 1 6 30 41 12 1 3 7 200

Frequency 1 1 2 2 2 2 2 2 1 1 2 2 2 2 1 1 1 27

%-Frequency 3.70 3.70 7.41 7.41 7.41 7.41 7.41 7.41 3.70 3.70 7.41 7.41 7.41 7.41 3.70 3.70 3.70 100

3A 1 0 3 2 5 2 3 3 3 0 2 5 5 3 0 0 3 40

3B 0 2 3 2 5 4 2 2 0 1 2 4 5 3 1 2 0 38

Abundance 1 2 6 4 10 6 5 5 3 1 4 9 10 6 1 2 3 78

%-Abundance 1.28 2.56 7.69 5.13 12.82 7.69 6.41 6.41 3.85 1.28 5.13 11.54 12.82 7.69 1.28 2.56 3.85 100

Prominence Value 4.99 6.27 15.10 12.54 20.23 15.10 13.82 13.82 7.55 4.99 12.54 18.95 20.23 15.10 4.99 6.27 7.55 200

SAPLING SEEDLING

Ca

nth

ium

b.

Ch

ryso

ba

lan

us

i.

Cin

na

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.

De

cke

nia

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Dille

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f.

Dio

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s.

Me

me

cylo

n e

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Ne

ph

rosp

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a v

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Pa

nd

an

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Pa

rag

en

ipa

w.

Ph

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nic

op

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Po

ute

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To

tal

Ch

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ba

lan

us

i.

Cin

na

mo

mu

m v

.

Ery

thro

xylu

m s

.

Lud

ia m

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Me

me

cylo

n e

.

Ne

ph

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erm

a v

.

Pa

rag

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ipa

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Ph

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nic

op

ho

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m b

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Po

ute

ria

o.

Sy

zyg

ium

j.

Sy

zyg

ium

w.

To

tal

3A 42 1 4 1 1 3 7 1 5 24 3 92 3A 30 16 5 14 3 3 2 2 75

3B 1 52 7 2 3 2 21 2 90 3B 11 62 1 2 5 2 1 2 86

Sum 1 94 8 4 1 1 5 10 1 7 45 5 182 Sum 41 78 5 1 16 8 3 2 3 2 2 161

Frequency 1 2 2 1 1 1 2 2 1 2 2 2 19 Fr. 2 2 1 1 2 2 1 1 2 1 1 16

%-Frequency 5.26 10.53 10.53 5.26 5.26 5.26 10.53 10.53 5.26 10.53 10.53 10.53 100 %-Fr. 12.50 12.50 6.25 6.25 12.50 12.50 6.25 6.25 12.50 6.25 6.25 100

3A 0 6 1 2 1 1 2 3 1 3 5 2 27 3A 5 4 3 0 4 2 2 0 2 0 2 24

3B 1 6 3 0 0 0 2 2 0 2 5 2 23 3B 4 6 0 1 2 3 0 2 1 2 0 21

Abundance 1 12 4 2 1 1 4 5 1 5 10 4 50 Ab. 9 10 3 1 6 5 2 2 3 2 2 45

%-Abundance 2.00 24.00 8.00 4.00 2.00 2.00 8.00 10.00 2.00 10.00 20.00 8.00 100 %-Ab. 20.00 22.22 6.67 2.22 13.33 11.11 4.44 4.44 6.67 4.44 4.44 100

Prominence Value 7.26 34.53 18.53 9.26 7.26 7.26 18.53 20.53 7.26 20.53 30.53 18.53 200 PV 32.50 34.72 12.92 8.47 25.83 23.61 10.69 10.69 19.17 10.69 10.69 200

endemic invasive indigenous alien

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix E -

Fire Risk Map: Geoprocessing Models

Model for Topography-based parameters:

Model for Anthropogenic-based parameters:

Model for Vegetation-based parameter:

Vegetation Survey and GIS-based Zonation of the Fond

D’Albaretz Forest, Praslin, Seychelles

- Appendix F -

List of planted species in the burned area

Aphloia seychellensis Bois merles 19

Brexia madagascariensis Bois cateau 28

Canthium bibracteatum Bois dur rouge 54

Deckenia nobilis Palmiste 2

Diospyros seychellarum Bois sagaye 8

Dodonaea viscosa Bois de reinette 55

Dracaena reflexa Bois chandelle blanc 4

Intsia bijuga Gaiac 7

Nephrosperma vanhoutteanum Latanier millepatte 105

Northea hornei Capucin 1

Ochrosia oppositifolia Bois chauve souris 66

Paragenipa wrightii Café marron grande feuille 19

Phoenicophorium borsigianum Latanier feuille 25

Pittosporum senacia wrightii Bois joli coeur 101

Psychotria sp. Bois couleuvre 3

Syzygium wrightii Bois pomme 108

Tarenna sechellensis Bois dur bleu 15

Damaged plants 7

Total 627

Plantings, 11th and 18th of October 2008